>>88757734if you mean over Mattie, she's not Mattie but if you mean over Danny it's because of his powers.
If he can turn Danny, he'd be the perfect surrogate son; Mattie's child with his powers, it's the perfect power fantasy for him, even more than just getting his dream girl he'd have the perfect son. Of course he wants both but getting one or the other is still preferable. Jazz is the dull bronze medal