My dad is almost 87 and has one as well.
Whether he knows how to work certain functions is another story....seriously. He can make calls, check the weather, scroll his favorite web sites and play solitaire. But downloading tickets and adding them to his wallet would be a serious, serious challenge IMO.
I've had my challenges a couple times with the ticket app, and feel reasonably versed on technology. The glitches I experienced would've thrown my dad into a tizzy. I just ran point on a software implementation (coordination basically), so I generally know how technology functions, talks and is connected. But when you have a glitch it can be pretty frustrating; especially for someone 80+ y/o
This also means I'm probably about the same age as your old man.