Upvote:7
In short, this is a complicated legal issue. Your friend is married to two different people, without the knowledge of his first wife, and in potential violation of Canadian law which bans polygamy.
The questions here amount to a request for legal advice, and the complexity of the situation is well beyond what an internet forum can provide. Your friend needs a well-qualified lawyer to help answer these questions, and many other relevant ones; not merely an immigration consultant who can help prepare paperwork, but an attorney who is able to research the relevant law and advise on the risks and benefits of various courses of action.
Upvote:9
I'm going to dissent a bit from the general gist here since I'm not so sure this is all that complicated. If your friend had married both wives prior to coming to Canada CIC would only have recognized the first marriage and would treat the second spouse as if no relationship existed. The second wife would have no relative in Canada, the daughter might or might not have one depending on the basis for the adoption (if it depended on the marriage it might be considered nonexistent as well). Whether a visa application would be successful is a different issue, but if the second wife behaved consistently with their view that any prior relationship did not survive the husband's move to Canada this might work out. There is an article here discussing this that includes a CIC memo on the topic.
Unfortunately this is apparently not what happened. Instead I understand what happened to be that your friend moved to Canada with his only wife at the time and then, after becoming a permanent resident, acquired the second wife. This is a clear violation of Canada's bigamy law, an indictable offense punishable by up to 5 years in prison. If Canada found evidence that your friend had done this then, whether the second wife visited Canada or not, this very well might jeopardize not only his immigrant status but his freedom.
When your friend moved to Canada he voluntarily subjected himself to Canadian law from that point forward. I don't know what it says about your friend that he ignored his obligation to observe those laws, but I suspect it would be in his best interest for his second wife to not have any interaction with a Canadian official who might, even accidentally, come to know the facts of what occurred.