Fives can't be revived. When another 501st Clone Trooper ally would be defeated while Fives is active, they recover 100% Health and Fives is defeated instead.
If Fives is defeated this way, 501st Clone Trooper allies gain his Max Health, Max Protection, Speed, and Offense stats in addition to their own until the end of battle.
Clearly states the following function:
If would be defeated (after damage done! - how else it would work?)
Fives intervenes
Fives heals them to 100% (shock etc interrupts this mechanic, so 1hp)
Now comes the second...
They gain fives Max health, Max prot (gain also protection this way of course...), Speed and Offense
Doesnt work simply as it is.