URGENT!: How do I trace somebody living in another country (non-relation)?

[James]

My friend has lost contact with her brother. We know his name, his wives name and his two sons names, who are all said to live in Canada. The brother was before a British Citizen for 23 years before they lost contact. I am a British citizen trying to research this guy.

Obviously I am not related to her brother or the rest of the family but is there anyway I can find out even if these people are a family and whether they do in fact live in Canada or if actually the information we have is false? All I need to know is whether this man does exist and if he does live in Canada with a wife and sons.
So does anybody know how I can work this out/trace them? Maybe through marital documents, census's, birth certificates etc. Do I need to be related to him and do I need a valid reason for it? How much can I found out, how do I go about it and what are the conditions? Or is this an impossible task? Really need somebody with experience to give advice. How much can somebody with no genetic relation find out? Where or who would I have to contact to get this information from?

Thank you in advance