Thank you everyone! I was feeling like I must have been such a slacker and just "glossed" him over when I brushed or bathed him. Max's hair is so totally different!
I intend for him to be cut short when he's groomed, but I was ashamed to be taking him in there with such mats in his hair. I wish I could take a photo of it, but my digital is dead at the moment and I don't think the cellphone would really get it.
You said a metal comb....so before I go out and buy the wrong kind, is there a certain brand or style of metal comb?
I don't mind spending a couple (or several) hours to work the mats out, but it would be great if I didn't have to do it on a regular basis...just keep him mat-less once the big job is done! I worked on him for at least 2 hours last night, and he was SO GOOD! I know it wasn't pleasant for him, but he didnt' whine or yip or anything. I thought maybe he knew he'd feel better without them.
I had been using a Pantene conditioner on his coat, but rinsed it out. I'm going to get some Cowboy Magic when I can, but what is a good leave-in conditioner? It's been forever since I've used anything leave-in, so I'm clueless and I know there's a ton of them out there.
Is a dematting comb something that shaves the mat out? I hate to remove too much of any hair that he's got; poor little guy. He didn't get the good hair gene I guess. I was hoping it was a nutritional issue, but now that he's almost 8 lbs

up from 2 1/2 in March

, I'm not so sure of that. Someone did say though, that it could take them 4-6 months to recover from a starvation mode, so I'm holding out hope

.
Thank you, thank you, thank you to everyone who responded. I don't feel like such a negligent owner now and am encouraged to take the time to just work them out! I really appreciate your help!