I don't know about any of that but I keep hearing that the government continues to print out more and more money, as opposed to bitcoins where there's a limited amount.
My guess is your dad doesn't have a giant trash can full of dollar bills as an investment. He likely has investments in ASSETS (equity in companies, bonds, real estate, etc) while those assets may be valued in dollars (i.e. 1 share of google is $886) the asset has value independent of what a dollar is worth. Printing more dollars doesn't reduce the value of the asset, and it doesn't increase their value either although the nominal price in USD will rise. The rising price is simply a reflection of the falling value of the dollar.