To me the situation is pretty straight forward. He has given his all for us, scored a ton of goals, been a match winner on many occasions, and taken us all the way to the CL Final. Before the season started we could never dream of that.
He told us from early o'clock that he wanted to go to Boca, so it's not like he all of a sudden is trying to screw us over. If he doesn't believe in the team getting to a CL Final again next year then he needs to leave, as we don't need people with that attitude playing for us, even though returning to a final right away is very unlikely. Motivation is huge in sports, and an unmotivated player is useless individually and also rubs off on others around him.
If he goes to Boca i will be fine with it and thank him for proudly wearing the #10 and performing for the team. It's his childhood dream after all. However, if he goes to PSG or Atleti, that's a different scenario and I could understand fans being pretty pissed off about that. Either way he has given his all and played amazingly for us while donning the #10 jersey, which is a lot of pressure. I'm grateful for his contribution and will respect his decision.