To be fair though, a patron isn't exactly an NPC in the traditional sense. If you're an Old One Patron warlock, I really, really doubt that whatever old one you draw from is even aware of your existence. ((or, perhaps, heaven help you if it does

))
And, the thing is, that sort of thinking tends to make players REALLY gun shy about making any sort of connections to the anyone or anything in the game. Your patron betrays you is almost cliche by now. It's to the point where an NPC that doesn't stab you in the back is a pleasant surprise.
One mechanic that I saw in a game called Chronica Feudalis is something I do love. It's called Background. Not background as in where your character came from, but, background as in something not in the foreground. The player gets to delineate two or three things about his character that are in the Background. They are true for the campaign but, the DM is specifically not supposed to do anything with it. So, if your Background was, say, Extended Family - then maybe you have relatives all over the place and everywhere you go, you meet (or can choose to meet) them. But, the DM is not allowed to center any play around that. So no kidnapping a sister, nobody gets into trouble and needs to be bailed out, that sort of thing.
I tend to treat things like Warlock Patrons the same way. I'd be very, very careful messing with a player's Patron in any way. That's a major part of that character. I would always talk to the player beforehand before making any sort of change in the relationship between the PC and the Patron.
I've found that this approach means that players will stop coming to the table with Man with no Name characters who are orphans who just arrived in town on a ship/caravan from very, very far away.