I think Bolton will be eligible to play against the Crows.
The following rule for 21 day concussion protocol is the best I could find to explain the scenario, which we can use to work out the 12 day concussion protocol.
Essentially, we play the crows on day 12, which in the example is day 21,and if he passes all protocols and receives medical clearance, it seems he can play.
..."The day on which the concussion is sustained is Day 0. Day 1 of the minimum 21-day protocol is the day after the match, namely Sunday 2 June.
The player will, at a minimum, miss the next 2 Saturday fixtures (i.e. the match on Saturday 7 June and the match on Saturday 14 June).
However, as Saturday 21 June is the 21st day after the day on which the player suffered the concussion, the player may potentially return to play in the match on Saturday 21 June, assuming that the player has safely progressed through the 3 stages of the protocol and been approved by their medical practitioner to return to play."