What a mess..

What was your 10 yr old son doing alone with 2 dogs kown to not get along?
What are 2 dogs doing being left alone together after knowing what your Beagle does period?

You stick your hand in a dog fight your gonna get bit and if you dont well you are damn lucky but it's always a slim slim chance you wont get bit..

You and your whole family need to work on the dog not just pawn him off to someone else because your not being a good owner.

Start doing NILIF with him and get him into obedience.