Well i`ve breed my bettas and when she releases her eggs they both catch them but I cant tell if they are eating them or not because I cant see them in his nest!And how can I tell when they are done?about when will the eggs hatch?

When the female catches the eggs, you can be pretty sure she will eat them. In the betta family the male is the caring father, and he will pick them up in his mouth and push them back up into the bubble nest. Altough, if it is his first try as a father, he might eat them as well. He will get the hang of it the next time.....
It is very hard to see the eggs in the nest at first. Its easier to see if you shine a flash light from the bottom into the nest, and even then you need good eyes. After a few days it will get easier, then you can find little mini fish inside the eggs.
YOu can tell if they are done when the male starts to chase away the female, even trying to hurt or kill her as soon as she gets too close to the nest. Then its time to take the female out....