If he has fine fur and always lies on one side, he may just need more brushing on that side to remove loose hair.

I have a Maine Coon that gets mats (even tho I brush him often) and I have two methods for removing mats.

1. Grasp the knot of hair closest to the skin so you're not tugging on the skin as you work on the mat. I then use a comb and start working from the end of the mat toward the skin.

2. If the mat is really large and tightly matted, I'll hold the mat (don't want to ever cut the cat's skin) and cut vertically into the mat with sissors. Then, using my fingers and a comb I can work the remaining mat loose. For safety, you can place a comb between the mat and the cat's skin so you don't cut him. (Grooming sissors that have blunt ends are the safest around pets.)

I doubt he needs regular bathing, but you may want to try one of the waterless shampoos that are available. I've used the foam types since my cats don't like anything that has spray-nozzle noises. But, you may first want to try one of the detangling products made specifically for cats.

The mats have a similar appearance to fish scales and are on both sides of his body. It would be easier if they were just one mat not just half inch in size but very tightly matted.

I had a cat once that would get clumps of fur when she was shedding. She would actually let me just gently tug the tufts and they would come off. They weren't actual mats, just clumps that came loose when shedding.

These are mats. Having had both short and long hairs over perhaps 40 years I have seen all kinds and worked on most but these are very tight even after one night. I brush and comb the side that he allows as he allows me. In the past I took scissors and carefully separated the hairs until the mass was loosened then brushed. He is not allowing that right now.