The oil change will be interesting, but if he’s a success at it once, he has a new skill.
Before anyone drives the car, it would be prudent to at least check the oil level. Someone else, maybe.
Open the hood, find the engine oil dipstick, and pull it out slowly. Wipe the end with a paper towel, and note its markings.
Now put the dipstick back in to its full depth, and slowly pull it out again. Observe the oil line at the bottom of the dipstick. It should be between the low mark and the full mark.
This tells you that you have an adequate level of oil in the engine. (But it doesn't tell you if you have an oil leak.) Only subsequent checks will tell you that, or noticing oil on your garage floor.