Wolfie, when my frog got into a filter accident, he was in TERRIBLE shape. He was extremely pale, swimming in a very 'floaty' way, and obviously having trouble battling the suction from a filter that he previously had no problems with. In my case, the filter was covered with nylon mesh, but the entire intake fell off and into the tank - poor Speckles was sucked INTO my HOB filter, and possibly could have been in there for hours before I saw what had happened. It was a very dramatic, frightening accident - frustrating after I had done everything to avoid a filter incident!
I moved him to a hospital tank in a dark and quiet area in my home - out of the community, and 'helped' poor little Specks to the top of a bit of Hornwort floating at the top of the tank. He also did not avoid me or try to get away. . .he was too weak. . . and he rested there (with the lights out) for an entire day before coming back down. With his injuries, it was easier for him to be close to the water line so that he didn't have to swim up for a breath of air. By the 48 hour mark, he was starting to LOOK normal again (regaining color), but still very inactive for what I had come to expect from him - and refusing to eat. Overnight on the 3rd day I got him to finally take a tiny bit of food. . . soon after he started acting and eating normally again. About a week after the accident he did a 'damage shed' to remove the skin that had gotten messed up during his ordeal. . .
The point is that today he is 100% FINE, except for a tear in one of his flippers, which does not seem to affect him at all. . .really, there is nothing that you can do but leave him alone, keep the lights out so he can rest peacefully, and hope/pray for the best. These frogs are a lot tougher than they seem in many ways - hopefully he's just taking it easy and letting his body heal. I'd just leave him alone for now... but be observant, and keep an eye out for any redness on his skin.
Just for the record, I've never seen my frog sleep at the top of the tank, though he does do his zen thing up there from time to time when he's in his happy place. He spends less time up there now that he's gotten a bit older, and from what I've read younger frogs will spend more time at the surface than older ones - this doesn't apply to the accident, though.
They ARE more active at night, so I like to feed mine at around 6ish in the evening. I've found that feeding him when he naturally starts waking up for the day (lol) ensures that I get to watch him for a while before *I* go to bed at night - though he will happily take food at whatever time of day I offer it, and he IS active during the day, too. . . just not as much happy swimmy froggy action as in the evenings/nights - and I really LIKE to see him being froggy!
Although you're right - one of the signs of sickness or injury is that the frog doesn't try to escape when you try to catch or touch it, in the future you might find that this no longer applies. I hand-fed Specks for a bit when he was in a community tank, and at this point he comes running every time he sees my hands in his tank (even though I gave him his own space months ago). When I do my water changes, I have to work around him, because he shows no fear - and he's healthy as a horse (um, frog)! Right now your frog isn't feeling well, and so won't be trying to get away - just leave him. I just wanted to mention it so that you know it isn't ALWAYS the case - and a friendly frog is a super sweet thing to enjoy!
Has he eaten since he got hurt? If he eats, it's a good sign that he's starting to feel better. Try to feed him tonight - like NOW, lol - and keep an eye on him for a while after and see what he does . . .
Hopefully something in this entirely too long post will help you out! I wish I could tell you something more -I don't know where our Gizmo has gotten to lately - she's had WAAAAY more experience with these frogs than I. . .
I really hope he pulls through.
Poor little guy! *hugs*