Whether or not you believe Henry Winter would travel simply to cover Rashford's charity work, you still have no proof whatsoever to say that wasn't the case.
@Rolaholic has also stated in an above reply that Henry Winter actually did travel to cover these Rashford contributions multiple times in the past, when Rashford said nothing of wanting to leave.
I don't see how your second point is even relevant. Rashford obviously hasn't been able to turn it around, hence why he is looking to leave and has made these comments at this point in the season, likely with a view to moving elsewhere in January.