I had the exact thin happen to me this last spring. One of my chicks developed a cross beak at two weeks old. Unfortunately, it is showing up right before their first big growth spurt and will continue to get worse. Mine was able to eat until ten weeks old and at that point she let me know she was ready to go. I culled her after she went to bed with an empty crop even though she tried to eat all day. I checked her crop every night. She was a fighter and lasted quite awhile with her severely crossed beak, but the moment she showed me she was done fighting was when I knew it was time.
Good luck, it's a terrible deformity but you can fight for the chick like I did and see what happens. I made different feeders as the beak got worse and somehow my chick managed to adapt. I would just try and not get too attached and be aware that you don't want to breed something like that.