Could be gramps busted the collarbone in the scuffle, then sank down his headlock right proper-like.
You don't have to crush a larynx to kill someone in a headlock. Just sink it properly & squeeze down, the larynx going in the crook of the elbow, the forearm & biceps muscles constricting the blood vessels on the side of the neck. Unconsciousness* comes in seconds, death in minutes.
If his larynx was not crushed, the above is a likely cause of death.
Anyway, I'm downing a beer in honor of gramps & his buddies this PM. Considering I just got diagnosed with pneumonia, gramps could likely kick my *expletive deleted*ss around the block and make me cry like a little girl.
* Done the uncoscious-part to others in training & had others do same to me. DO NOT think you're gonna be a tough guy & wait until you're on the edge of going out before tapping. That is a good way to end up napping on the mat. Tap as soon as your opponent has it sunk properly & call it good 'nuff.