Cú's not going to try and change her mind about going there. If her mind is made up and wants to fight— look he's not going to deny anyone that (in fact, he respects that determination greatly). Though he is going to do the protective Bonded routine, cuz that's how he rolls

Maybe they could do some epic Witches' Fightin' together with combo spells and what not

Or one gets hurt the other protects
Also to consider: Northern Post, leyline, they're both Witches and there's a lot magic going on