Or other comfy/scruffy clothes/loungewear.
DH had a major OP 12 weeks ago. To begin with he wore the new PJs he bought to go into hospital, around the house. Navy blue button through traditional style PJs with a collar. He was comfortable and looked fine. Now, he's graduated to getting "dressed" in comfy joggers and an old fleece. OMG he looks like a tramp! He has a huge incision across his middle, so I completely sympathise with him wanting to wear something stretchy.
Similarly, I have a pair of PJ bottoms in a brushed woven cotton which hold their shape and look much better for lounging around than joggers do IMO.
When dressed for relaxing at home AIBU to think PJs are the best option? I'll add I don't mean the actual PJs you slept in.