[kjc]

Hi and Welcome Back to YT!

The next step would be to follow the vet's instructions, get the ear problem under control, and get some of the weight off him and reaccess him at that time. If he's still having problems, then more may need to be done. There's a good chance that fixing his ears and losing some weight could be all he needs right now. If, at any time, his symptoms get worse, or he developes new symptoms, I would call the vet to make him aware and to see if the vet needs to re-examine him.
He may just be getting tired by afternoon/evening, hence his weakness causing falls/missteps. Try to schedule any of his strenuous activities for earlier in the day, and allow him ample rest time later in the day.

Good luck with him, and keep us updated of his progress...