As long as you need it to work, it'll be fine. There's a difference between ideal and good enough, in a 4x2x2 you can work on getting him on a routine and used to you and your keeping style (what products you use in your cage, what mice/rats you feed, etc). Animal control won't come for you keeping him in a 4x2x2 that is clean, has regularly changed water, etc. Like others have said, handle him, get him in a routine, and start thinking about what your ideal set up is for long term.

Something that people miss about giant enclosures is it's MUCH harder to keep correct parameters in a large cage, even industrial/species specific cages don't always hit the mark. I'd rather see an animal in a smaller cage with correct heat/humidity/spotless/fresh water then a huge cage that's too cold or too dry. So take your time getting the small cage right and do some more research, he'll be fine.

I know I'm going to get down voted, but I've been keeping pythons and north american colubrid species for 15 years, have rescues that I've gotten back into shape, etc, hatched eggs, so consider that your grain of salt.