As someone who has been on the opposite side of this scenario (diagnosed bipolar) the best thing your friend can do is get professional help. Since he’s refusing that, there’s not much you can do other than taking care of yourself and trying to minimize the damage from his episode. You won’t be able to talk him into it. He has to come to the decision that he wants to get better himself.

There’s a good chance he will get worse before he gets better. He may become a danger to you or himself. If he has never been diagnosed with a mental health issue he may blame you for it as you forced a confrontation with reality when you called the crisis line.

If you really wanna play psych nurse (which you will eventually be forced to if you continue living with him while his condition is untreated/unmanaged)start by declaring your home a drug and alcohol free zone. If he has a taste for them he’ll probably go get them on his own anyway, but increasing the barrier to access decreases the risk of other life altering mistakes. Try to make sure he eats enough and stays hydrated.

My recommendation would be to give him an ultimatum: he gets into some kind of treatment or you go your separate ways. It doesn’t have to be psych care. I found going to a support group incredibly helpful when I was first coming to grips with my disorder. Before I found a specific group for bipolar I went to a couple AA meetings even though I wouldn’t call myself an alcoholic. Being with other people and watching them confront their demons can often make it easier to start facing your own.

You are a good friend and it sucks your friend is going through this. But if you are not a trained mental healthcare professional you are not equipped to handle this.