Possibly... but there is also the point of, he's their friend.
And their reliable, so if they want you to join them, and you know you will be depended on, even if it isn't for what you perceive as great, you know they perceive it as great, so what's the loss? you're valued.
We've seen how much they enjoy his skills, and how useful it is to them. So I doubt they would be the type of party to not value MC, although they will tease him cause they're foster parents of the girl.