well, iam not an IO, but i honestly dont think a 35 marrying a 55 lady is for anything but immigration, if both are the same age it would be perfect,but with this huge age differnce, his chances are very low, unless he truely loves her and the relation is genuine,then he should provid solid proof.
this is my personal opinion,i could be 100% mistaken.
you can read on the cic website and get all the info you need and the forms you need to fill
http://www.cic.gc.ca/english/immigrate/sponsor/index.aspgood luck!