Changing spark plugs after 127K

“I don’t think he’s willfully ignoring these things…I just don’t believe they occur to him. He’s really not car savvy in any way.”

He doesn’t need to be car savvy. All he has to be able to do is to open the glove compartment, take out the Owner’s Manual, and read what is specified for vehicle maintenance. If he has not done this in 9 years, I think that his apparent lack of maintenance IS willful.