It's not uncommon for kids to have lots of cavities. At that age,if parents aren't brushing and flossing for them and if they are on a high carb diet (think picky kids only eating crackers, breads, and drinking juices) they are prime candidates for cavities. At this age the molars are the important teeth the play a pretty big role in holding space and for function and they should be what you are most concerned with. Unless the front teeth need a pulpotomy you may be able to get away with fillings on the front teeth. You could always remove the two front teeth at this age because many of their peers will be losing teeth in the near future but they will be without their two front teeth for 1-2 years. If a child has that many cavities you may be better off putting crowns on the back teeth ( depending on location and size of caries) for longevity purposes. If you wanted to go really conservative you could put Silver Diamine fluoride on the carious teeth and delay treatment but that turns the cavities dark black. Anyway it's understandable that this is a shock to the system. No dentist would be offended if you got a second opinion. It might make you feel better too.