Question for Canada Only in regards to Visitor's visas*****?

I emailed the Canadian Emby but they just ignored my question. I just have a question if anyone knows for sure. I am a US Citizen and of course I know all I need is my pport to visit Canada but I have a minor son citizen of Costa Rica that lives in Costa Rica, "yeah in case u asked I had a girfriend there like 16 years ago and there you go" I want to take him to Canada for 3 weeks. Does he need a visitor's visa or just because Im a US citizen he wouldn't need it? and if he does, do I have to go all the way to Costa Rica to get his visa? im not the custodian father, but I am his father.