Greenwood was allegedly fragile before all this due to the suicide of his close friend. It was one of the reasons that Rangnick brought in a team of Sports Psychologists when he arrived. His career at Manchester United is surely over but MUFC will also be alert to being accused of abandoning a suffering young player that came through their academy too. If MG says sorry, the club will almost certainly send him out on loan for a year or two.
Fans will not forget but he is also not the first Footballer to do wrong and continued their career. He is 20, he needs to acknowledge his wrongs, pay for the damages caused and learn from this. If he does this, he could get back on track. Part of his rehab in years to come will be forgiving himself and focusing on his career again, probably in another country. Lots of tough lessons for him to come.