So, I noticed some kind of tumor on his testes (yep, I had decided to leave him intact) and the vet felt the best solution is to neuter him (we won't know what it is until he is neutered).
If everything comes back okay with his pre-op blood panel, I'm taking him in on Friday morning before work.
Please spare some good thoughts, I am a bit stressed even though it's a routine procedure, since he is almost 12.