Sounds like you’ve thought about this a bit so you’ll be fine. Everything you may need can be bought in route if necessary. Perhaps download offline maps for your navigation app in case you don’t have cell service.
Maybe pack some healthy food? This is going to sound silly, but I like to buy small heads of green and purple cabbage and just eat the leaves raw while driving. It can keep you from buying junk at a gas station.
You could do some worst case prep, like have a couple gallons of water in the car and other things to keep yourself alive and comfortable in case the car breaks down somewhere inconvienent. If you have time you can buy a roadside assistance plan from AAA or similar so you can get towed to a mechanic, but you very likely won’t need it.
I’ve been driving for over 20 years and I’ve never had a car break down in route. Just make sure the tire pressure is fine, the tires aren’t shit, and there are adequate levels of engine oil and engine coolant. That’s all you can really do.
I bet if your parents seduced him he’d probably be more open to having sex in their house.