PLEASE, ITS A LIFE AND DEATH SITUATION

[islamsucks]

a Russian Jewish woman got married not by Halacha in 1954 in Russia to a Jewish man, they later got a divorced also not by halacha, the woman married another Jewish man also not by halacha, and they have children and grandchildren, are those children and grandchildren considered to be mamzerim

[OdKahaneChai]

Is the guy married already?

[judeanoncapta]

a Russian Jewish woman got married not by Halacha in 1954 in Russia to a Jewish man, they later got a divorced also not by halacha, the woman married another Jewish man also not by halacha, and they have children and grandchildren, are those children and grandchildren considered to be mamzerim

I'm not a posek, but it would seem according to everything that I have learned  that the children are not mamzerim since there was never any kiddushin and therefore no need for gerushin.

[Tzvi Ben Roshel1]

a Russian Jewish woman got married not by Halacha in 1954 in Russia to a Jewish man, they later got a divorced also not by halacha, the woman married another Jewish man also not by halacha, and they have children and grandchildren, are those children and grandchildren considered to be mamzerim

I'm not a posek, but it would seem according to everything that I have learned  that the children are not mamzerim since there was never any kiddushin and therefore no need for gerushin.

Its not as simple as that because one of the ways that people get married is threw the act (which is now forbidden completly, and one of the Rabbis put a curse on someone who gets married like that) I dont know for sure, but thats my guess.
 I belive that Kiddushin was either threw the man giving something to his future wife, or threw making the contract (like they do on the wedding night or by the act. (Now a days the first 2 are done, the last is forbidden, but if it was done it could be a problem).
Anyway the Rabbis I sent to him, would definitly understand, and be able to tell him what to do and what status etc.

[islamsucks]

Is the guy married already?

the guy you mean my friend? no

[OdKahaneChai]

a Russian Jewish woman got married not by Halacha in 1954 in Russia to a Jewish man, they later got a divorced also not by halacha, the woman married another Jewish man also not by halacha, and they have children and grandchildren, are those children and grandchildren considered to be mamzerim

I'm not a posek, but it would seem according to everything that I have learned  that the children are not mamzerim since there was never any kiddushin and therefore no need for gerushin.

Not necessarily...

Rov Henken rules that as long as at some point, two Shomer Shabbos people saw them together as husband and wife, then they're still considered to be married.