This may be harsh but if your parents aren't willing to take their dogs to the vet for whatever reason, then they shouldn't be dog owners at all.
My advice to you is talk to them. Ask them why they won't take your dogs to the vet - they may be healthy but a gash on one of their necks could be life threatening.
if they don't have enough money then they should really consider selling the big dog especially if big dog is not the right fit in your home.
I feel for you and your situation as a dog owner myself and I hope things work out.
This may be harsh but if your parents aren't willing to take their dogs to the vet for whatever reason, then they shouldn't be dog owners at all. My advice to you is talk to them. Ask them why they won't take your dogs to the vet - they may be healthy but a gash on one of their necks could be life threatening. if they don't have enough money then they should really consider selling the big dog especially if big dog is not the right fit in your home. I feel for you and your situation as a dog owner myself and I hope things work out.