I only have one perspective really.

You have a child,a child that needs healthy people around them.
A child that understands it ok to care but not to get used up.
A child that needs to understand he greatest help is when we help ourselves.
A child that knows that love means that both people give equally to each other.
You have a child that deserves to see their mummy laughing and smiling.

This spirituality he is describing is his illness, and he is too fixated on it being the right thing that he will keep you up all night talking over and over but only making sense to himself.
He isn't in touch with the real world, and in that respect cannot love the real person that is you.

, go enjoy your holiday and wait until his episode is over before you agree to see him,If you still feel you must.

Be careful he doesn't try and convince you he is better just so you will see him. Meet him in a public place to keep control of the conversation.

If he is certain he doesn't need help, I think you know what's right.Ask yourself,
Can I do this day after day, week after week, month after month, year in year out?

I suggest looking for support from people actually in your situation. Partners and relatives of BP/schizophrenia sufferers.
In fact talk to his relatives, they are your best source of information and support.
Out of interest do you know if he is "preaching/teaching" his form of spirituality to others, I just wonder if he has another outlet for all this energy. And you said he wanted to pass it on. Was curious as to if he has himself someone he shares this with?