NAH

Your feelings are perfectly valid. Your dad must’ve known how it would look if he invested into his step children’s property.

However, it sounds like your father is investing into the house he is living in, not his step children. They will benefit ultimately but it’s for him and his wife right now.

Your father is a bit TA in general for letting his relationship with his children get so strained. As an adult, you bear some responsibility now, though. While it looks like you’re trying, you did miss his wedding. He could’ve said it in a better way but it seems like he’s some reasons to be worried that you’re only in contact for financial reasons.