Hi Sanied
If your nephew is a compulsive gambler, then that will undoubtedly have caused his depression and it is the gambling that needs to be addressed. If this is correct then, in my opinion, he would probably get better support from a dedicated gambling addiction counsellor or therapist.
Your post does make sense but it has thrown up a lot of different problems and I would like time to give you a full answer. I will, therefore, post again tomorrow and hopefully communicate with you in real time tomorrow evening in an F&F group between 7 – 8 pm.
Velvet