My son goes to visit his paternal grandparent with his father occasionally. They are very nice people, DS loves them and I am really pleased they have a good relationship
He came back from visiting them yesterday (they live in a different city some hours away from me), and told me in conversation that they had both fallen asleep at the wheel and had accidents within a very brief period, causing some injury to themselves and writing off a car. His father (my ex), says it's none of my business and he can decide that they are safe to drive DS around. I'd rather he drove when they visited. He says no.
Do I have any recourse at all? I don't want to try to prevent the visits as they don't happen very often (and I'm not sure I could anyway).