It may well be that this attitude has been conveyed so far (even if I think you are clearly exaggerating here), but that doesn't mean it will stay that way. A good part of what makes a story a good story is that characters change as a result of the events they are confronted with. As I said, there's a whole storyline planned in which Dylan deliberately brings his mother together with other guys. In a storyline like this, a Dylan who agrees with everything right from the start would be boring. It's better if Dylan is jealous at first, but later learns that sharing can have its advantages (such as a few good voyeur events), too.Technically my comment about Dylan being possessive is accurate because even when he allows things to happen, like the photoshoot and the trampoline, he still sulks and feels angry about it. Sophia might be his mother but she's not his property. Dylan reminds me a lot of my brother and he's a total prick too
Another thing, good characters in a story always have positive and negative sides. That's why I prefer a character like Dylan much more than Sam, for example, who is just perfect in everything.