That's unfortunate to hear, because I bought my elderly mom the Pixel LTE watch for the same purpose after she refused a medical device. I figured as a consumer device the watch wasn't going to be as effective as a medical device for falls, but most elderly people won't wear a medical device due to stigma, will take it off frequently, etc., so at least the LTE watch is stylish and non-stigmatizing. My mom loves it, actually, but it's a bit moot if it's not even detecting hard falls.
I suspected this might be the case and figured the majority of hard falls aren't likely to result in a loss of consciousness anyway, or at least not for more than a moment. I figure she'd be more likely to voice dial 911 via the watch or press the crown button five times, so it's better than nothing. I also added about four Google Nest speakers around her house and bought the Nest Aware addon for 911 dialing.