SPOILER ALERT!!! (Read at your own expense)
Hmmm.... I think based on the spoilers, after he got his revenge and everything, he realized that the only family that truly mattered to him was the one connected to him by blood.
If I remember correctly, there was a time when his aunt, before she got assassinated, tried to help him (dunno, I forgot)? So by the time he made a wish, the resolve of sticking and protecting his aunt that he considered as his only family, he went back in time.
Btw, the current timeline is Judith's 3rd life so basically it was her own doing that she made Luca suffer in her previous life but she forgot all about that and thought that the original Judith was a different person.
Anyways, that is what I found so far but as to how accurate it is, I don't know...
SPOILERS
Judith really did care for Luca. She did what she did mainly because she thought she was doing the right thing and trusted the wrong person(Franz). Luca realized this late. Judith and Ruediger are major components to Luca's wish.
So we know "what" he wished for but I wanna know "why"