Without going into details, my group got itself captured by the band of mercenaries. Before they kill them, they will interrogate them to learn who sent them. One of the PCs is a droid, damaged and deactivated. So in this case, they will try to access his memory. I understand this is a Computers check vs what for a PC droid? The PC droids work a bit differently in the game rules, for example a restraining bolt rule. Should the droid PC role Resilience? Discipline?

Sure. Use their numbers as the Difficulty.

I'd do Discipline. Maybe give the slicers a couple Boosts because the droid is "unconscious," and therefore unable to fight back properly, and call it a day.

Interestingly, I'm in a similar place wroth my party: they've been captured, and their droid's memory banks are about to be raised. The fact that the droid is a banker droid is not helpful to the party at all right now.