Hello
Seromas can take quite a long time to resolve. I have seen it take weeks. Or even 2-3 months. The key is that it is never bothering your dog and never shows any signs of being n infection.
In my experience it just has to reabsorb on its own and on its own time.
Badly healed breaks can cause lifelong mobility issues. He might be fine now, but what about in a year? 5 years?
Cats are pretty stoic. I’ll bet he’s in pain and just not showing you.