I’m no expert, but it seems to me like he might be a little constipated. When my rabbit wasn’t passing enough poop but eating fine, I often realised she was quite bloated. I took her to the vet and she turned out to be constipated. She was acting fine, eating fine, just not pooping or drinking enough water.
My vet suggested I feed my rabbit some olive oil using a syringe (the one used for medicine), he said that it would help lubricate his insides and pass the food easier. If your rabbit has eaten some of the carpet, it’s fine, the olive oil should help clear that.
My vet also suggested I put some olive oil… inside her butt by cleaning the syringe and (VERY CAREFULLY) putting it inside her butt However he knows I have a lot of experience with rabbits so I wouldn’t accidentally hurt the rabbit. But (no pun intended) I only use the butt method when she is not pooping at all.
I don’t know if that is a good or bad thing to do, but my vey suggested it, and I have been using that method everytime my rabbits are constipated and it works ALL THE TIME. Within just a few minutes they start pooping a lot again.
If your worried about him being dehydrated, give him some lettuce. A single piece of lettuce will surely not cause that much harm.
Best of luck
<3