I know we have all had at least one person in our lives, at one point or another, who isn't a family member, that we've been worried about. Sometimes you can actually do something to help this person you care about. But many times there is nothing you can actually do. Even when you make it known that you are there for them, and would do anything in the world for them, you really can't DO anything. Well, at least not until they are able to accept whatever help you can offer.
Perhaps they are in a position where any help they accept could cause other issues including making their life less tolerable. Perhaps they have other influences in their life that can't be easily changed, even if they WANT to change them. Perhaps they know what steps they should take to make their life happier overall, but they feel like they have to sacrifice their own happiness to please someone else. Maybe they just feel like they don't have the emotional strength to make the changes they know they need to make. There are so many variables, there is no way they can all be considered.
Often we don't really know exactly what influences they are experiencing. Other times, we know exactly, but again can't actually do anything.
There is no recourse other than letting this person we care about know that no matter what happens in their life or yours that you will be there to help in any way possible. All we can do is care about them, love them, be there when they need us. Never give up on them even if it's too difficult for them to send just a quick text or email to say "Thank you for caring about me. I'm ok."
Until such time as any help you can give can be accepted, all we can do is be there when they need us. This, in my opinion, is what REAL friendship is.