Put the trash can on the counter where he cannot reach it.
Use bungee cords to fasten the top on it so if the dog knocks it over, it won't pop open.
Remind the parents that if the dog eats trash and ends up with an intestinal blockage, they'll have either a huge vet bill or the nightmare of the dog dying in agony at home. Makes baby locks seem much more logical, doesn't it??
Housebreaking is easy; leash dog to you, when you see him squat, scoop him up and take him outside. At night, crate him.