Help find a person in Canada

[Аннушка Александровна]

Hello! Please tell me whom to contact in Russia or Canada. A strange situation has developed in our family. During the Second World War, my great-grandfather disappeared. Some time ago, my father (the grandson of a missing grandfather) began to tell strange things. Allegedly great-grandfather was captured and, together with the Ukrainian units, was released by the Americans. As a result, great-grandfather was in Canada. Return, of course, could not. In Canada, he started a new family in which three sons were born. Great-grandfather made good money and part of it decided to bequeath to the first son of one of his daughters in Russia (i.e. my father). After the death of his great-grandfather, his eldest son tracked down my father and somehow contacted him, apparently, to fulfill the will of the deceased. According to my father, he doesn’t need anything. And he sent a certain young lady and their supposedly joint child to receive an inheritance.
Of course it sounds like Santa Barbara. I myself understand this. The only way to understand whether my father is in his mind is to find the children of my great-grandfather and ask them all. The information is very fragmentary, because my father (the recipient of the inheritance) wants to leave everything to “his last” child, and also says that Canadian relatives do not want to communicate with the rest.
Information:
-Russian name of the great-grandfather (in Canada he changed the surname or the whole name)
- Names of the three sons of the great-grandfather (Philip, Zahar and Ivan)
-year of the birth of Philip (eldest son of his great-grandfather)