need to stop a truck from cranking

[26Troadster]

i need a little help. my father inlaw has dementia,
and snuck off in his truck yesterday.
drove about 40 miles to the airport thinking he is
still working and was looking for his workers.
he asked a officer where they were and he took my fil
into his care till family could get there.
i know i had a 88 jimmy s15 that if i disconnected
the water temp sender the truck would not start.
i hope it can be this easy on his. his truck is a
08 gmc 4 wd v8. anything easy to stop it from cranking?
thanks in advance.

[hatzie]

Pull the starter relay?
If he had any mechanical/electrical knowhow when he still had all his faculties you may have to remove the battery or just store the truck elsewhere.

I had a grandfather with Alzheimers back in the 90's. It's a rough ride especially if you had a decent relationship with them. They're dying in fits and starts. It tears your heart out.
A year into his decline gramps thought I was his brother Charles who died a decade before I was born. That was a blessing when I had to retrieve him from the area he lived in in the late 1930's. He got lost looking for the campground and travel trailer he and my grandmother lived in before they could afford a house.
My grandmother made me take the car away after that incident.

[26Troadster]

that is what someone else said too. that should be easy enough to find. i'm too old school for my own good. yes he has been like a dad to me for the last 37 years, a very smart man. it is rough to see this happening and i know my wife is tore up. thanks, that is what i'll do.