Don’t approach someone in that apparent condition (reading the FB post) unless you are honestly trying to help them to get help out of concern as a friend. I understand he stole something of yours, but if his family is really noticing a mental health crisis, put that first over ‘working it out’ to get your drone back. If he still has it, helping him to get help may also get your stuff back later, especially sincenthe police aren’t helping you.
Good luck, I know it’s hard, had the same thing happen with a good friend that ended up taking money and stuff and then cutting every friend he knew off from his life as he went over to the dark side.