Betta fry aren't your typical fish fry like guppies or mollys. Personally I think it was pretty silly of your friend to do this as the chances of the fry surviving now are pretty low, but here is what I suggest. They need their own tank (not a net in a community tank), the tank needs to be about 80F (warmer is better than cooler). They need live baby brine shrimp for food (frozen if live isn't an option). They need daily water changes, water needs to be conditioned, aged and same temp as old water. They need fed 4-6 times a day, since there are only 2, the portions needs to be very small so the water quality doesn't drop. That's what comes to my mind now....keep in mind, it is very likely the fry will get sick with velvet or ick, so keep an eye out for that so you can treat it right away, and be prepared for them to not survive. Maybe your friend can give you a couple of juviniles when they get older (about a month or 2 old), they would have a better chance of survival then. Good luck.
Linda