Have they filed annulment in the Philippines as well before receiving her PR? Just wondering...
Annulment is not required. One can apply for and be granted a divorce in Canada, regardless if the other spouse in Philippines wants to cooperate. The divorce will be legal in Canada, but not in Philippines (so they could re-marry in Canada, but never in Philippines).
Or as mentioned she could simply become common-law and get sponsored that way. There really is no need for divorce/annulment in either country.