Sleep is unimportant. Yes it is vital for human survival but only once in a while. When sleep finally takes them the night interrupted by horrible images, stories if you will. Nightmares, as most would call them. Nightmares reminding them that things can never go back, that they failed. Reminding them that that they failed to protect them, that they failed to accomplish the goal. They have a chance to change that, and it sleep is the price then that is a small price to pay for justice.
(Yes I referred to myself in the third person, no you should no worry)