Pre-made raw is good choice....unfortunitely it is very expensive to feed two large dogs with it. What you could do is feed a better quality kibble one meal, and raw another...or even 2-3 raw meals per week.
It does sound like your boy may have this problem no matter how much brushing or what you feed...it's common with BYB dogs because they don't breed for coat or looks...or almost anything...as long as they can breed.
I still suggest you get the dogs on a better kibble, you will need to feed far less of a good quality kibble....and it probably does not come out to cost much more per feeding. Canidae is probably the most cost effective food out of all of the super premium foods...it would be a good food to start with.
Gina