moving chesty bun inside permanently

I need help I have had lot of personal stuff and to cap it all off with the cold snap here Evans chest is really playing up he only has the one functioning lung so all chesty signs are worrying have discussed with my vet and he seems better in a warm humid environment he also needs quite close monitoring. My problem is my bunnies were never meant to be indoors I have quite limited space. However if being inside is best for him I will do so.
How do I make the most out of a bad situation? Outside he has a 8x6 shed with two 6x4 runs attached inside he and Dana will have a rabbit cage with one pen attached so its half the space and he has to be supervised constantly in the house as he destroys everythingso how to I properly bunny proof.
I'm at my wits end I can't help feeling I will be cheating him out of space although he can't really run around so much as he gets out of breath
I'm at a loss really any help appreciated I have so much going on at minute I worry he's being neglected

I think this would be better under Health, maybe you should start another thread in order to get some b etter advice.

Thank you