Bob, we gave our musical grandson a harmonica
I don't think he likes it..
Good luck with all of you're s.
Do a Sam Olson, and post on Youtube.
What would likely help, you probably already did.
Expose him to some good harmonica music.
My Dad used to get his out once in a while and I loved hearing him play.
With encouragement and patience, Dad could have taught me. Like so many things, there were many other priorities and distractions.
That reminds me that I should do the same for church.
We used to have a pianist and uke.