Fabian had always felt sorry for Elijah. They were both their father's sons, but why was Fabian the only one being acknowledged?
He couldn't completely agree with his father's decision to offer to take care of Elijah.
A mother wouldn't give up her son just because his father wanted him, so Fabian understood why Mabel refused the offer. She was dead set on marrying Welden, but circumstances didn't allow it.
However, Fabian still carried the guilt of not sharing his comfortable and luxurious life with Elijah, his own hal-brother.
He learned about this a little too late. Sofie had already entered their household by then, so there was no way that Welden could marry Mabel.
Moreover, Mabel was probably angry that Welden came too late that she wouldn't accept him if he indeed came.