To be near. Sometimes this is enough. It is not necessary to move to a loved one, especially if he does not ask about it. Just remind him of your phone number, ask him to call if something happens or becomes lonely and dreary. And keep your promises if you agreed to help.
Remember the boundaries of the other person. There are several situations in which it is worth breaking borders and taking responsibility for someone else's life. For example, if you know that a person has lost consciousness right now or is in danger. Then you need to go to the other end of the city - even despite the late time. Or call an ambulance or the police.
More often than not, people want to help deal with grief or depression. In these cases, obsessive help can destroy a person. It is worth letting him make decisions himself if he is capable of it.
Help in finding a specialist. If you understand that you can’t do it on your own, find a specialist: psychologist, psychiatrist, doctor, trainer.
Make sure he has the right competencies. For example, make an appointment and talk about the problems of a loved one. Find out what techniques he uses to help and how effective they are.