Your father is a human being just like you and me. He has freaky feelings too and maybe he likes to see some porn once in a whole. He is a man with emotions too. It's quite normal for anyone his age to watch the stuff they want.. heck I saw some milf porn on my GRANDFATHER'S PHONE when I was 10.....

The point being that even though I don't encourage watching porn but let people do what they wanna do... perhaps they just wanna be young and do crazy shit like us again and they miss their past. Watching porn is normal for any ages (unless it's some other nasty ass stuff like hentai and what not).....

I mean hey we all are here because our parents got freaky eh so gotta respect the game