How can I help my fiance with his mental illness?

Im sorry about your situation, I hope that he finds a reason to listen to you. Unfortunately my boyfriend and I are going through something similar. I have bipolar and he has depression and he insists on doing the same thing over and over that doesn't work well. Worrying about money, going to sleep around 5am, not applying for a better job, and so many other things he just let's pile up in his head. I hope there is something that will humble him into understanding that he can't do it on his own and realize what a pit he is in. The problem with this is he will slowly bring you down as you help him if he doesn't accept the help. I would recommend making an action plan for yourself and asking close relatives to help. If you feel comfortable telling mature kind people let them help you help him. I get therapy for under $50 at a drug rehabilitation place. It seems like therapy and medication is unavailable or too expensive but go to a clinic that is mostly government paid and you will receive care, to start until he can make enough money to get better quality help! I wish you the best of luck! Make sure to value yourself in this whole process, caring for him doesn't make you weak and caring for yourself doesn't make you selfish!