What is the most reliable way to find my father in the Lower Mainland, BC?

You should contact a Private Investigator in British Columbia in the city where your father lives and see if he can find him. I'm sure if you have your father's name then it will be easy for the PI to find him. Also, make sure that this PI is reliable and that you are able to trust him or her. You can also try calling City Hall in the city where your father is from and seeing if they have any record of where he may be located. Good luck in finding your father.