Runny nose, sneezing

I'm fairly certain Galen has a URI, since he's got a runny nose and is sneezing a lot. His eyes are fine, and his voice was hoarse for about a day but then it got better. I've been putting l-lysine in both his and Dukhat's food to help, and took Galen in the bathroom while I took a shower so that the steam could help unblock his nose. Should I take him to the vet right now, or are there other home remedies that I can use?

There is actually little a vet can do for URI other than let it run its course and give you antibiotics to ward against any illnesses that may try to attack the immune system while he is already sick.

That being said, I have seen URIs turn fatal in a matter of 48 hours

Only you know how bad he is, I would at least call your vet and speak to them and ask