Hi, I'm sorry for your loss, especially your son. It's possible that he was just not healthy when you bought him and it caught up with him. That's the tough thing about buying dragons (any reptile) from a pet store vs an experienced breeder. Don't give up, I've had mine about 2 1/2 months and have learned a lot and am really enjoying my little shoulder-riding buddy. Out of the pet store, books from the pet store and this website - you can trust this web site hands down. I read this site day after day for weeks before getting my beardie so I felt very comfortable in setting up my viv and pretty much what to expect. I learned how wrong the pet store workers are about their care - they are telling you what they read on care sheets provided by.....the company and more people who don't know. The books, if you check, are usually years old and outdated. Good luck with the other beardie, I hope your son enjoys him!
Jennifer