Sorry to hear about your Dad. Honestly, I have never heard of this before, and am not clear as to what they feel the danger would be. Something about blood flow no doubt. Perhaps a Chiro. could best answer about the concerns and the possible dangers. Doctors are very interesting though. When I went to one that diagnosed neck Arthritis, one said there is nothing you can do, and take a pain pill. Another doctor said you need long term therapy. End result? I saw a Chiro., and a few years after I saw a different doctor who couldn't believe I had neck arthritis at all, since the movement was exceptional. Sounds like a consult may be in order. Sorry I could not be of more help.
