How should I deal with insomnia in my spouse?

Aromatherapy. I agree iwth dr. Viramgama. How about using some aromatherapy. Aromatherapy can help to promote deeper sleep and to increase sleep time. Lavender, chamomile & ylang-ylang essential oils are beneficial.
Improve sleep. (1) by improving his sleep consider improving sleep hygiene and sleep restriction therapy for spouse. (2) sleep restriction therapy mean go to bed only when sleepy and wake up same time irrespective of what time sleep happen. Only be in bed when sleepy otherwise out of bed. Eg. Go to bed at 1am if only that time sleepy and not early and wake up at 6am even if not slept well.