Maternal/paternal in the same way as the victims parents themselves were when they came out and defended him because they didn't want to lose their cash cow. If he was rubbish at football he'd have been long gone.They could well be motivated by paternal/maternal reasons to try and keep him and rehabilitate - much like a mum and dad would do if it was there son.
I'm not convinced this will happen over a long period of time. It will be like that at first but a few weeks in and everyone gets used to it, especially if he starts playing well and scoring, then it will die down and it will be forgotten by most. The home fans will sing his name and drown out the away fans taunts. It will only get brought up again when people start asking why we're not including him in England squads.He will forever be judged, his team will not be able to cope with the barrage of hatred and bile directed at him and all associated with him from a baying mob wanting his life in football ended.
Utd have the luxury of having enough fans that the principled ones that stop going will be easily replaceable and it won't cost them a penny in ticket sales.