Here is an article in the NY Times about sleeping pills and the elderly from a couple of years back. Seems a CDC study (online here) reported that it is not a good mix. Here is the most potent paragraph in the NY Times article:

The data also showed that Ambien, the use of which has soared in recent years, accounted for one in five E.R. visits among those older than 65, more than any other medication.

Concern over prescribing medication as a sleep aid for the elderly prompted this comment by a well known geriatrician:

“I’m not comfortable writing a prescription for these medications,” said Dr. Cara Tannenbaum, the geriatrician at the University of Montreal who led the weaning study. “I haven’t prescribed a sedative-hypnotic in 15 years.”

So what should an elderly person with insomnia do?

Well, I am elderly, 74 years old, and I use the Transition Trek method of getting to sleep as presented in In Pursuit of Sleep. I have found it practically foolproof. I use it every night, multiple times if necessary, and it works every time.