I do see your point, but the problem is with both of them. Their communication skills suck.
In Jackson's case he feels he has nothing to offer Casey and so in a way he rejected Casey from the moment he was born by relegating him to the position of just his ward. He thinks he knows what's best for Casey without asking him first. Later more will be explained as they get to know each other in new ways.
In Casey's case until recently he thought he was attracted to someone who was out of his reach. For a sixteen-year-old to be attracted to someone who to all intents and purposes had raised him would be frightening. Not to mention the fact Jackson is so much older than Casey. Later he will learn more about both his mates and they will have to learn how to get along.
What they both need to do is talk, alone, or with Vash there as a mediator.
Vash is the impartial being in this mating. He only knows both of them as they are now. He hasn't grown up with Casey and hasn't been raised by Jackson. I think he will have his work cut out to get his other two mates talking.
I hope this answers your concerns, but do feel free to comment again or message me with any other concerns.
Thank you for commenting and I am so sorry I missed this comment and so took so long to answer