Well, you might want to remind your dad that Canadian soldiers have been using cannabis to treat PTSD for a long time. It was used during the Korean War to calm nerves, for example.
You might want to ask a serving member of our armed forces what the deal is before you go spouting off about what you know
Veterans use and have used cannabis for many years, yes, however if you are actively serving and are prescribed cannabis then you cannot be actively deployed and you will be either 1: removed from your post if in theater or 2: if not in theather and still have time left to complete in the forces you will be removed from any supervisory roll or command
One of my very good friends is stationed in Ontario, runs one of the shooting ranges at CFB Pettawawa, and is fairly broken .... it has been suggested to him by a few doctors to use cannabis but if he goes that route he looses his command as well as at the very best being posted to the reserves or at the very worst being honorably discharged early due to medical which in both cases would split his retirement income in half due to him not completing the contract that was agreed upon when entering the service
Might want to get your info straight before you start going off about vets and actively serving members of our forces ....
TL;DR if my boy goes to cannabis as an active member he loses his active status and half his pension (and the guy has been in 2 wars as well as a few minor confilcts in 20 years of service)