My local shade tree mechanic (and neighbor) is a nice guy but I wouldn’t trust my car with him. I’m friendly with the guy, and on hot summer days, I’ll usually bring him a beer or a coke and he’s appreciative and I appreciate that he is appreciative.
I have observed him draining the coolant and just leaving it on the street while it flows into the sewer system. Green stuff.
I have also observed him tape up a customer’s torn ignition coil pack with electrical tape. I think you’re supposed to replace it.