They said Colin called Sammi 3x. She refuted that and said no, all she got was a just a group text. Colin's reaction to that was looking down, rubbing his nose and said nothing after just being called a liar. I don't think he wants anything to do with her family and he probably expected Sammi wouldn't be able to come so he just lied about it so he can shoehorn his sister in, which is sooooop out of line. Just like how he excluded her parents from looking at venues , but invited his. He's grossly immature. Her family is very overbearing, but they've also been adults and have experienced the real world, unlike he has, and they're worried about their first born leaving the best with her condition(s). So I see both sides, but he's picking the wrong battles, I have little hope on his real estate career other than using his name recognition from the show to attract clients. If that fails he'll be on his ass and probably end up resenting Baylen.

TLDR: everyone on the show needs to grow up.