His ability applies when he is in torpor.
200754
Karif al Numair
G5Sabbat: During your turn, you can lock or unlock another ready Black Hand vampire. Black Hand. +1 bleed. +1 strength.
Rulings
Black Hand is not a title, it is a trait unrelated to any sect. The trait is not lost if the vampire changes sect.
If a minion who is attempting to block is locked, then that block will fail, unless they woke earlier during the action.