If he understand the no and leave it, then that's a good start. I think you need to go beyond that and redirect too. Get him completely away from the situation altogether. Don't give him the chance to stare and growl. Remove the dog completely from the room if you have to. Change what he's focusing on.
A stare and growl can turn into an attack very quickly with an unstable dog and the wrong move. Not saying your dog is completely unstable, but it's not a good sign when he's growling at family members either.
How old is he by the way? Has this ever happened before with anyone else?
And if he doesn't want to be friends with your father, that's fine. The staring and the growling is completely unacceptable though. It shouldn't be allowed. You need to keep his focus off your dad and on you.
I most definitely would not classify my dog as unstable, and while yes to me my dad is family, to my dog, my dog probably doesn't see him as part of the "pack". Like I said, its a temporary living situation, we are kind of interlopers here for a few more days, aside from this one time he's been very well behaved, par for the course for him.
the dog is 3, never happened before with someone he is familiar with, he's not a particularly barky dog, and never growls. The only time I have ever seen behavior like this was walking him at night and a neighbor standing in between some cars said hi and startled me, kind of did the same thing, but he was on leash. Like I said, I know the trigger was being me being startled, he's just being protective.
I don't think he would ever bite, like I said, he had ample opportunity before I called him off this morning, and just barked and growled, but I guess my main question is how do I make him understand who is in "permanent okay, don't worry about them" status? I'd figured having been around my family occasionally since I've owned him, and living here for the past couple of weeks, he'd get that, but apparently not.
But yes, you are correct, that behavior is not okay, and will not be tolerated. Trust me, I'm not a "mean dog" kind of guy.