Dear RVS JI,
COGRATS FOR GETTING MR LETTER.
Please be advised that ur son can have his medical done in Canada itself. After he under goes his medical, he may send his passport + Medical completion form SINGNED BY DMO + copy of his passport duly verified/attested by DMO (IF POSSIBLE) through someone who is likely to visit India ,at the earliest, for handing over the same to u for its onward submission to VO ALONG WITH THE DOCS,AS CALLED FOR , IN UR MR LETTER.
Good luck ND MAY GOD BLESS ALL !!!
parhar51