back to a real question, do u think that i caused the timing belt to slip by starting it?
If you tried to start the car before the RAC arrived and it sounded sick then you probably did it no favours. However, the father in law still tried to turn the car over after he'd been warned not too - also being a mechanic he really should have known better.
The guy sounds like a bully. I know from experience of the wifes cousin don't take money off an inlaw for a house - you are forever in their pocket and would seem to give them the right to speak poorly of you at every opportunity.
Makes you wonder how some people tick.