Hi Donna...I don't know that serious matting problems in F1 coats have been discussed before and, frankly, I don't have an answer for you. My F1s have never had the type of coat to mat. Sorry that I can't help, but I am sure that someone here will be able to.
I would just suggest lots of brushing, several times a day if necessary. There is a good chance that his puppy coat is changing to the adult, but I don't know if that would cause matting.
I'll be watching for the answers from others too...we have some people who are groomers on this site, I'm sure they can help.