I'd say fairly involved.
Him and my mom would take us kids to their friends house where they would have some drinks and play Mario Bros on NES.
I distinctly remember my mother leaning forward every time Mario would hit a coin block.
After that my mom kind of fell out of it, with only a brief resurgence many many many years later when she joined my dad again playing Tiger Woods golf.
My dad however has always played since then. Never played much N64 or SNES, but he loved Final Fantasy 7 and the Playstation in general. He's the one who bought Diablo for the PS and set me down that incredible path forever more.
Playstation took up a lot of his time. He was way into Diablo, Front Mission 3, Final Fantasy Tactics and Panzer/Allied General. I do believe he didn't get to play the PS2 when it launched much, however he made up for it long after the consoles hay days by getting embroiled in Champions of Norrath, Final Fantasy 12, and the afore mentioned Tiger Woods.
When his life long friend whom, he would play golf with passed away from cancer, he stopped playing golf games altogether.
After I myself discovered Morrowind on the Xbox, I quickly turned him on to it, and before I knew it he had picked up a used Xbox and a copy of the game. He played extensively, and loved that game.
After he lost all the consoles, I caught him playing Diablo 2 on the PC. He had NEVER played a PC game, and I wasn't sure if he'd be able to adapt. But sure enough, every morning for the next month or so he'd be up with his coffee slaying the lord of terrors minions. Sometime after that I showed him Torchlight and he really liked it, and eventually got it as well.
Nowadays he's playing Path of Exile. I don't know how, that computer barely barely runs it, frequently dropping far past playable frame rates. But he never complains, never quits. Just keeps plugging along.
He's about 63 now by the way.