D.D.
I'm sure your friends would be honored to watch your son and would feel really bad to know you are worried about asking them. Sit down and have a conversation with them about it.
Since you have so much lead time before you go to the hospital, you could call them to give them "heads up" and maybe your son could go there to go to sleep.
Let them make the choice about whether or not your son will be too much for them- and trust them to give you honest feedback on what will or will not work for them.