Thanks for the feedback everyone. I have heard some mixed opinions elsewhere on the web about Life Alert (high pressure sales tactics). I've also heard to find out where the call center is (it should be in the U.S. not in India or elsewhere in Asia). I may check out ADT as I have them in my home for alarm monitoring, and I believe they offer an alert service for seniors.
My dad is very mobile; he drives every day unless there is ice on the road, and he will still drive on the highway as far as my sister's house (40 miles from where he lives). What brought this up was my friend's father-in-law who unfortunately was found deceased in his home by his son -- he apparently had a major heart attack the night before, and he fell to the floor and could not get to a phone to call 911. Also my aunt who is 6 years old than my dad fell and broke her hip several weeks ago. Luckily my uncle called for the ambulance right away, but the damage was done.
Not only do I have to convince him to wear a pendant, in a few months we will have our annual conversation which is me trying to convince him to let me get a snow shoveling service for him.