I do not understand the nature of the problem. Wait for what? Do you want to have children with him? That would be quasi-suicidal, or, at least, much worse than having a child with a sperm donor. What else might you want to wait for? You can continue seeing him and let the future unfold on its own, without too much intervention on your part. Just continue seeing him and maybe somebody else will come along eventually, without effort on your part.

There is no point in confronting him about his behavior - when his savings evaporate, he will need to confront reality on his own without your assistance.

You should not be trying to help him because it will be in vain. If you want to continue seeing him, that is OK, but do not set unrealistic goals about helping him. In other words, you need to get it - you either accept him the way he is or you do not.

It appears that you are somehow attracted to situations of high uncertainty - you report that you never know when you will see him. You can try buying lottery tickets, gambling small amounts of money, or thinking of other alternatives that have uncertain, low likelihood rewards.

You can try being more open with your dating partners apprising them of the fact that you have a concurrent attachment to a highly unusual individual who never leaves his house blaming his difficult childhood with his grandparents for his paranoia and untreated depression and that you would continue to see him from time to time. That would remove the element of cheating/deceit/risk and you can then see if you are still attracted, because it seems that the risk part is a draw for you just as the uncertainty of seeing or not seeing him is a draw for you - risk and uncertainty are basically two sides of the same coin.

You realize that it is highly unusual for a man to never leave his house, do you?