My father-in-law wanted only a few things in life.  The New York Times.  Walker Texas Ranger.  Concerts in the summer.  And his sleeping pills.  It was amazing how focused he was about his sleeping pills.

When we started to provide elder care for him in 2001 he was on Ambien.  As far as we knew, he was on that drug for years, when it should have been taken for two weeks at most.  He was also taking melatonin but we were not sure in what quantities.  We immediately threw away the Ambien.

In the beginning sleeping through the night was not a big issue.
It was during the last four years of home care that sleeplessness became an issue.  He started to ask for sleeping pills right after dinner.  We acquiesced by giving him melatonin.  He asked that we leave the bottle by his bedside.  When he woke up at night he would forget that he took some already and that some more.  The normal dosage was a 3 milligram tablet once a day.  To prevent an overdose we substituted 100 milligram Vitamin C tablets for the melatonin because they looked identical.
For a while we besieged his doctor for some kind of sleeping pill that would work because every one we tried failed to cause him to sleep.  His doctor helped us to understand that because of his underlying medical condition none of the sleeping pills would work.  They only make him more confused.
The best routine we could come up with was to be sure that he exercised every day.  Then at dinner time we would make him tomato soup using milk instead of water.  For dessert we would give him canned mandarin orange slices or some other canned fruit.
We tried to schedule bed time at the same time every day in order to establish some kind of routine.
Sometimes all this worked.  When it did not we tried to make up for lost sleep by napping when he was asleep during the day.