I'm gonna take a wild shot at this.
The datasheet appears to give Qg for Vds = 50V, Vgs = 10V and Vds = 50V, Vgs = 4.5V where the gate charge is typically 14.2nC and 6.7nC respectively. It can probably be assumed that the gate charge in your case (7.15V) will result in a Qg somewhere there between.
Since coulombs are C = IxT. And let's say we need to discharge a worst case ~14.2nC in a time period of 1% of the switching period (1 Mhz) which is 10e-8 then we'd need 1.46A during that period to discharge 14.2nC.
I'm not familar with exactly how fast you need to switch the mosfet in order to minimize switching losses but maybe this will help.