I agree that if he is working for Dad and still lives at home at age 33 and if he only has Obsessive Compulsive Disorder (OCD) and depression, (I have depression and it is very treatable and common) then he is functioning more like a ten year old than a grown man. My autistic son is 24 and works in the community and lives on his own. Your son has nothing about him that is so paralyzing that he shouldn't be able to function and pay his own bills and work for somebody unrelated to him. I certainly hope he doesn't have a car you provide for and pay for or even a cell phone you pay for. You have needs too and you can't live forever. Then what? If he do much as whispers suicide call 911. Bet he will stop doing it. Or at least he will be in professional hands if he is truly suicidal. You aren't a professional.
If he were my son, he would be evicted. My daughter took drugs and had to leave our house for that at 19 . She is now 34 with a two year college degree (her loan), a house, a long term boyfriend, my granddaughter and doesn't ask us for money. We are very close. She is thankful we made her leave, at least now, not at the time. Sometimes it takes that.
I really hope you give thought to not only his life once youre gone but your own quality of life while you are here. He is not your baby boy anymore. He is tall, with a deep voice, hair all over and society sees him as 33. He MAY qualify for SSI, Medicaid, food share and low income housing. It's a start. You can not help him or fix him or any other adult human being. It is all on him, as it is always on the person himself. It has not worked for you two to fix him so far. It won't.
He can not depend on you forever. If he is able bodied he can find a job where Dad isn't his tolerant boss. That's not real life. If he can work out (who pays for the gym?) he can do heavy work or even flip burgers and he may make some friends. That is within his abilities. He can get help for depression too and he has a lot of gall mooching off of you and refusing to get mental healthcare to help himself do better. That's his fault. I would insist he go for psychiatry and prove it to me by showing me each receipt or pack his bags. I am tough but I got results.
Love and light!!