Hi toomutch, Wow i'm sorry to hear that. I don't know what to tell you. Has he been in trouble or convicted of anything before this? IMO I would think since he is 16 and IF he hasn't been convicted of anything prior to this then with a good attorney they might be able to get the charges reduced to hopefully a misdemenor. Then he probably will have probation, fines, and maybe some type of classes to attend, counseling or something.
Most likely he won't get off scott-free. If he has had prior issues then its possible they will stick with the fraud charges. He will most likely have an arraignment and a pre-trial court date.
Hopefully he will have a good attorney that will enter some sort of plea bargain.
Thats about all I can offer you at this time since I am not an attorney. My other concern is your sister..... she might get some kind of rap too because she was responsible for those checks.
Its too bad kids start thier young life with stuff like this, but hopefully he will fear this enough.
Take Care