How to i get my dog back please help?

ok long story but please read for the sake of my dog ok 2 years ago i went over seas to visit my family and i left my dog with my dads friends and when we were o holidays they let the vdog walk without a leach he is trained but they were walking him on the highway near there house and long story short the dog got hit buy a car and they paid for the dog we tought them not do becouse we can afford it anway they paid for it then after that they spayed him (we were giong to to that 3 months after we came back) and then they took him home. we cant call the police becouse if he gets arrrested my dad will lose his bussnes becouse he ownes a share in bussnes and also we vsiad can we please have the dog back and they were like oh we paid for the surgery. i dont know what to do i love him so much he is my hole life (im 15) please help