Show him pics of the bloody soggy mess using birdshot makes. Not as deadly, wounds proficiently. At appropriate distancing and with proper shot placement. Ofcourse.12 gauge. For those times when you need to reach out and touch someone, up close and personal like!
I remember an idiot years ago on another gun forum criticized me for choosing a 12 gauge with buck-shot for home defense. Claimed it would tear up wall and leave a huge bloody mess to clean up if I had to use it.
Hmm...Well, if cleaning up blood and brain matter, and patching a few holes in drywall are the cost of keeping my loved ones safe, I'll pay that cost every day if I have to. Small sacrifice IMO.