The first thing I would try is brushing him gently while he’s eating. Don’t worry too much about getting hair out, just brush slowly and gently so he can get used to it and hopefully eating will help him associate it with positive things.
I’ve also had success with the clicker. Start with getting your bunny to touch the brush with his nose. Most bunnies are curious and will sniff whatever you’re holding, so click and treat when he bumps it. Once he’s excited about touching it, use the back of the brush (not the bristly part) to touch his back, then click and treat. Gradually work your way up to a brush stroke, then click treat. One of the keys to this is a high rate of reinforcement – you should be clicking and treating every 10 seconds or so to keep him interested and thinking about what will happen next. If he runs away, just sit quietly and see if he’ll come back to try again at an easier level.
My two already understand the clicker, so it was a bit faster, but they went from hating the brush (for years) to letting me brush them pretty extensively in only two 5 minute sessions. While brushing I continue to reinforce with treats, but now I can get in 5+ good brushes (getting lots of hair out) between treats. I use pellets because they’re small and easy to eat.
As far as brushes to use, it varies rabbit to rabbit. I have two lops, but one has very thick and soft hair while the other has slightly shorter and not quite as silky hair – technically they would have the same fur type, but I can tell the difference with which brushes work better. I like the hairbuster comb sold on BB and a slicker brush. The furminator pulls too much and they don’t like it. The hairbuster pulls a bit, but you can angle it differently to make it more gentle.