Roosters comb don't look the same

[roostercrazzy]

I searched in the forum but didnt see what I was looking for. I have a year old leghorn rooster whose comb was a nice red and stood up. Lately he's been dealing with a respiratory issue which is being treated. A couple days ago I noticed his comb as bright and it is starting to lay over. I'm not sure what to do. Please help.