I am stumped on if he's referring to man or Adam as mankind, he talks about in Book III which takes place in heaven, that he had free will but in books I & II it takes place in Hell and Satan determines the course of actions going on.
"Till one Greater Man
Restore us, and regain the blisful seat"
[1: 6]
Milton's poem is quite clear that whatever damage might have resulted from The Fall, every human freedom was restored by the Incarnation (treated at length in Paradise Regained).
Milton believes absolutely in human accountability, and in the Felix Culpa.
(Robert Graves has a very interesting theory on why Milton is so committed to this doctrinal position).
......
As for Satan's freedom of action - in Book 1 and elsewhere - remember what Milton tells us at line 209:
So stretcht out huge in length the Arch-fiend lay
Chain'd on the burning Lake, nor ever thence
Had ris'n or heav'd his head, but that the will
And high permission of all-ruling Heaven
Left him at large to his own dark designs,
Adam's freedom of action (and consequently, human freewill) is repeatedly established in this poem. Satan's freedom of action is presented only with conditions, and ironically.