Like I said, I've learned my lesson on several occasions when trying to tell an elder about gun safety. It never turns out pleasant. I was observant of his demeanor as well and could tell he wouldn't have been receptive towards my advice.
"Those with 1911s, put your safety on! Those with Glocks, keep your finger off the trigger!!!"
"Let's keep that weapon pointed at the floor, if you don't mind".
Always works for me.