I consider them to take care of their disabled as best they can.
A lot of stories have the disabled fluff be abused, but that’s just because people around here love abuse. (Personally I feel it’s the most boring outcome, since the disability gets no chance to shine - it’s just a prop to have a specific fluffy get hurt.)
If a fluffy is missing a leg or similar, it’s treated no worse than any other scar - fluffies can walk on three legs pretty well, and it’s not like high speed is an important factor for the little guys. A blind or deaf or derped fluffy may need nudging along and extra attention from whatever herd member likes it most, but will be considered as good a fluffy as any other. It’s not their fault they’re a bit of a silly dummy who can’t hear any good, after all. (This isn’t limited to disabilities either - an example is my one-shot Nu Num Fwuffies!, where a cannibal fluffy is born and the entire herd works together to watch over her and stop her from eating meat.)
If a fluffy is impossible for the herd to take care of, like it lost both front legs or got spinal damage or something, they try to find it a good owner or alternate home so it’ll be safe and happy. So you could have a herd asking a human to take in their crippled friend, or bringing it to a shelter, or similar. If another fluffy is extremely attached to the disabled one that fluffy can be its full-time caretaker, and possibly even drop out of the herd to stay with its friend.