Thank you for the reply, Rube. Yes, I also believe we did a good thing. The veterinarian said, even thought he's a pretty dog, if he went to the kennel, he would probably put down after a while, because people wouldn't want to adopt an already grown dog and because he's not in his best health. We can give him comfort for some years, I hope. About urinating in the house, he just did that in the first day, now he has been going to the garden and doing what he has to do outside, so he's a clever dog. He also sits and lies down when we tell him to.
We have been giving attention to both of the dogs, I even take him for walks outside the house and leave the new one inside, as he can't see very well and doesn't like to have a collar, so he just stays in the house. At night they sleep in the same room, and haven't done any noise, so I assume nothing bad will happen. We dog is just a bit a-social with other dogs, I don't if they will be good companions, but if they can coexist in the same house it would be nice.
