Come on, mate. Come on.
Mkhitaryan's best season of his life came form the RW/RF role at BVB. Mourinho played him where his performances had shone the brightest in the past. To say that he played him out wide where he's not effective is quite frankly bollox. He played him out right, he played him next to Ibra too last year, as a SS, in CL games. When his performances turned to shit there, he moved him to #10 where he'd see more of the ball. Hoping that the central role would suit his skillset more.
He had 3 good games, maayybe 4, at the start of the season. By the Everton game we were saying he was playing shit despite grabbing an assist. That was 17th of September. He played every following game, including CL games, until the 18th of November. That's 2 months he persevered with him through abysmal form. Compare that with Rashford/Martial where if one of them had a bad game he'd be on the bench, or sometimes be benched even after playing well. He put up with him when we were yelling at the TV for Mourinho to take him off.
These last few months Mkhi has barely looked like a footballer. Lost the ball nearly every time he got it, overrunning it and going down blind alleys, simple passes failed to meet their target, abysmal work rate. If he's mentally checked out that's more on him than Mourinho. He's certainly done nothing but justify he's omission from the squad so far, and that omission was not unwarranted at all.
I don't know about the play style not suiting the player. Maybe it doesn't, maybe it was bad scouting from the start. But you can't say that Mourinho did not treat him well or did not try to find a place in the team that would get the best out of him. He tried and persevered with him and Mkhi only got worse and worse. The fact that everyone would rather see Lingard ahead of him right now, shows how much he has fallen. And I'm afraid this total collapse is on Mkhi not on Mourinho.