Toenail problems.

We adopted Tiger (62lb what appears to be shepard/boxer mix) in May and about a month and a half later we noticed he was licking his foot and limping so we took him to the vet. They ended up removing a split/damaged/infected toenail under sedation, antibiotics, wrap, etc (very expensive). They also cut all his other nails very short and saw some issues with them. He has been going back to the vet almost every other week for a checkup. The removed nail seems to be healing quite well but he still has about 3 other nails that are split and the quick is separated from the top of the nail. He is currently taking a multivitamin and wearing the cone to prevent licking. We wipe his feet after going outside. My concern is the length of time it is taking all of this to heal. Our vet seems to be making no big deal out of this and says they are healing but we are approaching the 2 month mark of all of these issues. He is still eating and drinking but seems to be depressed. No limping. Occasionally there is a small amount of blood from the affected nails. I just want some kind of timeline. Should we take him to another vet? I am very worried about him and the fact that this is an ongoing issue. We want to do whatever we can for him but the vet bills are quickly adding up and I am hoping there is something more we can do at home for him. I have had dogs my entire life and I have never seen anything like this. As far as diet he eats Natural Balance Duck formula dry and canned.