If anyone wants him as head coach after managing the team like that. Let's face it, he has actually made Manchester United worse. He was the reason Ronaldo, the team's top scorer left the club because he didn't like him and didn't fit his idea. And in the end it turned out that Ronaldo was the key player. In general, a difficult man...
The Manchester United coach have needed upd a lot of times in the past and for the crisis that led to Christaina Renaldo's departure from the club is one among many noticeable flaws from the coach that have had a lot of negative impact on the club and that have become much more justified crisis at most and at times a lot also have made the coach to have acted in such manner and at that time and place.
But just as you have rightly said, be for Manchester United can make any remarkable progress and a comeback, there is a need to change a lot of things about the club and the first thing is to sack this coach and get a better replacement.