Will sleep return after discontinuing klonopin (clonazepam) for sleep?

Eventually: Depending on how long Klonopin (clonazepam) was taken, & at what dose, there may be withdrawal & rebound insomnia when it's stopped. It's usually better to taper off the dose than to stop 'cold turkey'. If the underlying reason for insomnia is still present, it will again disturb sleep after the med is stopped. Otherwise, the rebound insomnia may wear off in about a week (but it varies a lot).