Well, that's another way to a win/win: put a price on the business that would include some coaching, and sell it to him.
Let him know that you're pulling back, but will do some work from time to time as mood/money might dictate.
Keep only what you want to do the projects you like; you can rent or buy stuff later if need be.
The just-in-case stuff can be hard to let go, but I've been doing that lately and it's kind of liberating.
Maybe if your protege gets the stuff, you could rent/borrow it back if need be, so in that way it's mutually beneficial, but he stores the stuff.

Sometimes what I do on these matters is to step outside my head and look at the situation from outside, so to speak.
More than once, it's helped with clarity, or a better idea, or overcoming the "need" to hold on to things, mostly because that became comfortable and I hadn't noticed I was close to drowning under them.