My boyfriends family..

I love my boyfriend. And at first I loved his family too. As we date longer I just see what flaky people they are. So my boyfriend works with his father and brother along with two to three other guys and his father owns the company. He's mostly scouting jobs instead of working. A "confusion" of some sort happened where bf was paid more than expected. just now his dad calls insulting and saying how he broke a light and he now owes an extra $120 plus on top of what he was "overly paid". We think his stepmom and dad are wrong and I tried expressing my opinion and he just got defensive. More and more I begin to dislike his father. They took us to Vegas in Nov last year it was my bf and I, his brother and gf and his father and stepmom. The entire trip they constantly teased my bf and still do to this day. About his looks, his life, literally everything. To me it's become a dominant thing, his father and stepmother always trying to be more on top. He always tells me they're joking but knowing it affects him at times, I want to help in some way. He always says "it's just how my dad is, you don't get it".. Sorry needed to vent badly. suggestions ladies?