OK, mail him a gag gift but Dad lives in frigid Wisconsin and you live in balmy Arizona.
I suggest you fly him to AZ in the Spring when Wisconsin is still frozen and you two hike the Grand Canyon. If he is fit enough you could run Rim to Rim.
If you can't afford the money, at least find the time.
Southwest Airlines has some amazingly cheap fares on sale occasionally.
I was born when my Dad was 46 so he was always old compared to me.
Sooner than you think, your Dad will be too old to do cool stuff like hiking the Grand Canyon.
You will remember a hike/run of the Grand Canyon with your old man a lot longer than you will remember getting him a roll of Trump toilet paper.
FWIW, I am 56.