What changes have you made to your childs diet? The problem is adult teeth are now coming through and will decay in exactly the same way that the baby teeth have.
It doesnt matter what they have to eat or drink at meal times but it’s what they eat and drink inbetween and just before bed , even if its just a bite or a sip.
You are not just looking at sweets , biscuits cakes , but also starchy foods eg crisps , fruit juice , smoothies , granola bars , yoghurts , raisins etc
Just before bed time is a danger because if they have anything sweet or starchy to eat or drink just before bed , even if they brush their teeth afterwards , the acid attacks their teeth overnight.
Does your child graze and snack inbetween meals, do they sip on drinks?
Are you brushing their teeth for them with a fluoride containing toothpaste?
These teeth are coming out , from what you say , there is no saving them . No paedodontist is going to do extensive treatment that will fail on these teeth that are supposed to last another seven years. Neither are they going to do any other treatment especially until you get diet and cleaning under control.
Youve had a nasty shock with your child needing so much treatment . Now put your energies in the right direction , get the necessary treatment (extractions) sorted and make the changes now before you have the same problems with the adult teeth.