Let's get clear here, who is going to own the system, listen to it, and pay for it?
I can't tell if you're buying a system for your dad and sharing it, or do you have your own system and are trying to project onto him what he should have?
The $500 budget means little because we don't know if that's for a one pair of speakers, one pair plus a subwoofer, or all that plus an amp or receiver. We have no idea if it's for 2 channel music only or if there's a surround sound goal in the future. How big is the room, how far from the speakers does one sit and how loud does it need to go?
My son and I both play around with this "hobby". We have our own separate homes now and different goals are clear to each other. I buy him some stuff, he thanks me. I don't expect him to buy me anything, he's just getting going with home, career and family. What are you trying to achieve?
BTW, $500 doesn't get you a whole lot unless you find a great deal on used stuff or cheaper new items on clearance sale.