This is of course based on a lot of speculation and conjecture, but assuming something like the worst version of what's being reported is true, I'd say this:
We cannot allow a situation to arise where one individual player has the influence to sack our manager. That CANNOT happen. We can't allow that to be a standard for how our club works, I don't care how good the player is, it could be a prime Cristiano, that can't be allowed to happen.
I would sit them both down and tell them to grow up, park this issue, and get on wth their jobs. Pogba should just get his head down, play his game, and if Mourinho is as bad as PP thinks he is, he'll be gone soon anyway. Let Mourinho fall off the cliff himself, you don't need to be the one to push him. If he wants to go, he can f*ck off for all I care. I'd be tempted to get rid in January to be honest, lay down the gauntlet to Mourinho, sell Pogba and replace him with whatever Mourinho wants, and then give him January-May to prove himself, and if things don't improve significantly sack him in the summer. He isn't irreplaceable - yes he has all the ability in the world, but he hasn't consistently been close to being one of the best midfielders in the world for us. If Mourinho thinks he could do better with 1, maybe even 2 midfielders we could sign from the fee we'd receive for Pogba, I'd be tempted to go for it.
I think there's an argument that if the board publicly back Mourinho, it may unite the players under him, if (big IF) Pogba is the disruptive influence he's being made out to be. Or it tears everything apart and we crumble even more spectacularly than we already are. It's a tough one.
Bottom line is, if Pogba's actually attempting to create an environment within the club to get a manager sacked, who's to say he wouldn't do it again if he ends up not liking the next guy, and the guy after that? I'm just bored of the Pogba circus. I really like Pogba but his overall performances across the past 2 and a bit years hardly warrant the level of drama surrounding him we've seen had season. However, if things are being exaggerated and blown out of proportion by the media (highly possible), or if Mourinho is the aggressor, and the guiltier of the 2 parties - and if he loves United like he says he does and he wants to stay and fight for this club now and in the future, I'd encourage him to keep shtum for the next few months, be a model professional on and off the pitch, and let Mourinho cause his own downfall, and ensure he's here to lead the club when he's gone.
In an ideal world this can all be resolved, but I'm not sure I see it happening.
(P.S. Apologies for the long rambley post)