ISO of recommendation for medical alert device for elderly

[Anonymous]

I'm hoping that someone can offer advice on how to pick a medical alert device for a 90 year-old hearing impaired relative living alone. I'm looking for something along the lines of a panic button that can be worn and would call 911 and also alert his family.

There seem to be 100's of providers and I can't find any reliable reviews. Any chance someone here has first hand experience and can make a recommendation?