So... if Joseph of Arimathea believed that Jesus was going to rise from the dead, lending out the family plot for three days wasn't a big deal. It wasn't an act of generosity but of faith.
Well, that was an odd thing to say. For two reasons.
First, if we go by the narrative of the gospels (and if we aren't, what are we talking about?) Jesus' followers didn't actually expect him to rise from the dead, despite his hints in that direction.
Second, no-one discussed whether J. of A. was being
generous, the question is who paid for the tomb?
But since you bring it up, then (again, taking the gospel as gospel, so to speak) J. of A. must have had some stones. Peter denied even knowing Jesus three times before the cock crowed, whereas J. of A. "went in boldly unto Pilate, and craved the body of Jesus" and assisted Nicodemus in giving him a lavish funeral. Never mind being generous, if we are to believe the gospel account he was being
courageous.