Using personal car for their "service"...car is getting worn out
Also if you disagree with him he sends you snarky PM. Fuckwit.
Look, if you lent one of your kids (or stepkids) one of your older vehicles as a first car, good for you!
If you didn't "lay down the law" with said relative about how to treat, maintain, and let in the car, that is on YOU!
If you did not bother to look over the car's tires, engine, fluids, paint, shocks, exhaust, interior leather, etc for an entire YEAR, that is on YOU!!!
But will answer your question. If your relative was engaged in door-to-door field ministry as a regular pioneer racking up many hours per month, and this was a 4-door vehicle, than you can be damned sure that the Service Overseer or Group Overseer for any particular day, at some point in time, assigned a group of people to "your" vehicle throughout the month, and it racked up many, many miles. It would have been up to your relative to put their foot down and say "no, this is my parent's car, not mine, so we can't use it." But who under cult control is going to say that, and risk raised eyebrows, when they can instead be seen in a positive light?
If you are looking for someone to blame, look in the mirror. If it's your car in your name, this falls on you. If car is all messed up due to kids' treatment of it, there is an easy remedy for this: Immediate removal of car and kick them off your insurance. I'm saying this as a father AND a step-father whom taught my step-son to drive, loaned him $7,000 for a near-mint 2001 Audi TT (one owner, an older lady), and then watched him beat the shit out of it over the course of 4 years until it was unrecognizable. It took him 5 years to fully pay me back, which he did. He did pay for all repairs and insurance. It was a learning experience for myself, and him. I was responsible at 16. My father let me drive his BMW. Hell, I did the tune-ups and oil changes on it! Far cry from my step-son, who I had to show where the oil dip-stick was. My son on the other hand, could probably handle it. Either way, lesson learned. Some kids can handle nice things, others can't. Gotta gauge each one, and go from there.
An individual (non-JW, let's say) loans a car to a JW family member, to drive for a year.