Aside for Odom Harishon giving up 70 years of his life for David Hamelech, I am not aware (but please enlighten me) of any other instance in Jewish history that this has happened.
Gedolim and Talmidei Chachomim have been sick before, Yaakov Avinu was sick, Chizkiyahu Hamelech was sick and many others recorded in Chazal. Yet we never ever hear of this practice.
I do not believe any true Gedolim endorsed this – especially not if it is publicised like this.
If I am wrong please prove it – we live and learn.