It could just be as Curtiso says that Bailey's had his nose put out a bit by Einstein's arrival.
Jimmy really went into his shell when I brought Misty home, he skulked around with his tail down and spent most of his time hiding from her under the couch. He wouldn't even walk near her, he'd lollop along miserably taking as wide a detour as possible. Luckily this only went on for a few days and he started to get intrigued by her, Misty was a persistent little madam and determined to win him round.
I'd be inclined to make a big fuss of Bailey when out on your walks together and also try and play with him at home but not go overboard. I don't know how old Bailey is, Jimmy was about 20 months, if he's a lot older it might take longer for him to get used to the idea of Einstein being a constant presence.
Jimmy wasn't sick at all, I'm not sure how to explain that - but the weeing could be territory marking, especially if Einstien is weeing in the house.
I found that pushing them together didn't work, it's better to just leave the older dog to get used to the idea in his own time.
Good luck, I hope things improve soon.