you can increase his like by doing some stuff with him, like if you have beers a new option unlocks and just sticking around and giving him more beer gets more like. another way is during the fair buying him a treat and giving it to him or staying with him during the fireworks.
being with Bernard though doesn't affect your relationship with him at all.
you prolly reached the max amount for those interactions then, there might be a new option at Bernard's house at night to hang out with him, that might be a little later though, but you should check to make sure. also, by started with do you completed those 2 only or started with those 2 and finished the fair? because the fair is a good place for like with everyone in Bareshade.
