What is mental health? Do you know what a healthy mind is?  Unless you have studied to become a psychiatric nurse practitioner or other mental health professional, you may not have any idea. I think this is one of the reason's why so many people are struggling with mental illness, especially at these times, is because they do not know what is normal or healthy, nor do they know HOW to deal with what is normal or healthy--and when you think about it, it makes sense; if you do not know what is right or wrong you are likely to make mistakes; mistakes in your decisions, your judgment, your actions, your reactions, et cetera. You can scold someone or even yourself for your natural emotional reactions, which adds insult to injury, and further causes damage when there was no need. Haven't you ever suffered such? If you have, you know how much pain is caused when we do not know what we are doing and negatively respond to things in and around us.
I have seen children scolded for missing a parent or other loved ones when the adults are the ones that have their differences, and it hurts to see intentional pain inflicted on children because someone ones to get back at you. I give this as an example of what is normal and healthy and what is not...emotions are normal...these are things that rise up and change depending upon knowledge, but it is important to note that they are very rarely in our control when they rise up. We can all monitor and modulate our emotions as we need but we all have a point when we will--not might--explode, and it is at these times that man becomes a liability to himself--as his actions will be telling and probably bring him long-awaited consequences, so it is important to be careful in your mind, how you respond, what you think, and what you mind, i.e., think upon often.
We can all monitor and modulate our emotions as we need, but we all have a point when we will--not might--explode, and it is at these times, man becomes a liability to himself.
The subconscious mind is beautiful, at least to me, as it really is a cesspool, or it can become one if you are not careful. Then you are suffering from intrusive thoughts, that is, things coming into your mind and probably through your mouth almost without your permission--is this you?
It is one of the symptoms of post-traumatic stress disorder (PTSD), so it really just means you've been hurt and there is "something there," i.e., the residuals that are requiring you to work through what happened and to come to terms with it. 
This is why therapy is utile because it promotes this exact process; if you don't feel you need to go as far as therapy, that is up to you, as long as you are getting a sense of control over your mind and what you mind, as this is the first part of a healthy mind. It is the awareness of yourself as a person amongst many, and it is the awareness of your need to survive. 
This gives good brakes, hopefully, as people realize that life is not a joke and that it truly is about survival. This awareness naturally gives an intrinsic energy blast that boosts you forward to meet the tasks that your heart desires, and you move on through life by continuing to choose your survival, until one phase enters the next. 
One of the tasks the mind has to do is to monitor the information that it receives, and we have been living in a world of frequent information blasts, so my first question is, how are you doing? Have you been diligent in what you have exposed your mind to so that you don't have to find yourself feeling bogged down and struggling to extricate yourself from your surroundings in difficult times?
I have to say that I am religious about that, what I expose my mind to, so it is rarely running rampant through the day's tasks, which is good for me, as I can accomplish much.  How is your concentration?  I would say, if you find it difficult to concentrate, it is time to sit down and take stock of yourself and of what you are doing with your time. 
Eliminate what is perishable, i.e., it cannot maintain your growth.  For your information, concentration difficulties also coincide with PTSD, as it does with other mental ailments, so do not go about diagnosing yourself:  seek a professional.
Another aspect of a healthy mind, as I mention is growth. Is your mind forward seeking?  Is it vigorous about tasks in general?  A good mind loves doing, so no matter what it is, are you happy to just be?  
This can be ascertained by testing your ability to sit still and be content with that; the longer you do it, the better you will feel, I can attest. What are your future plans? Your goals? What is your working towards? Again, a healthy mind will be able to explain its doings, and such an individual will sometimes launch into detail because they are aware of the steps they are taking towards a reachable outcome.
The final attribute of a healthy mind that I would like to point out is love and how you respond to this emotion. How are your relationships?  Are you social? Friendly, even?  Hopefully not "too friendly," as this is a mind that is devoid of boundaries if this is ever proven to be true of you. 
As you can imagine, the whole planet needs love and we all receive and give love daily, in some form or another, each day. However, the question remains, how do you handle love?  Are you kind to it?  Are you kind to the people who are kind to you, and even to the ones that are not, as this is when love is defined?
Dictionary dot com says that love is "a profoundly tender, passionate affection for another person," and another definition said, such feelings for a family member, which both confirm my earlier definition that to love, is to be kind. Many people get distracted by another person's behavior and stop giving love, which just introduces hate. It is important to remember that distinction is important, as the mind is composed of reasoning elements that function on information: the older we get, the more we know, and distinctions help growth become applied.
When a child learns of matches as the source of an uncontrollable weapon, he or she will demonstrate that distinction through behavior around matches and other fire-causing elements, so it is important to note that distinctions are important for survival.
Many people have died from the coronavirus from not wearing a mask (I am talking specifically about the people who died before the government began mandating masks and even those around the world before we know what covid-19 was) and this great distinction continues to be an issue in unhealthy minds, I contend.
However, this is not about masks; it is about keeping yourself safe, as your future depends on it. It is about how you task your mind, what you chose to do with your mind and how you condition your mind.  It is like a muscle in this regard, as it can be trained in certain ways.
Good choices about how you train your mind will only advance your future, as it has a compounding effect.
Hopefully, these pointers were great and they helped you examine yourself further and who knows, maybe you can help a friend.
Good Luck!