Conversion facts

I heard in the name of Rabbi Y. Komietzki z"l from a very reliable source that if the father was a Jew and the mother a non Jew we should try to convert the child for the reason of zera kodesh - holy seed.


When I wrote to the Rebbe z'tl asking if my mother (goy) who converted after marrying my father (Jewish) the answer was 'She has to toivel again.'

Her initial conversion consisted of an orthodox rabbi in Long Island, NY telling her take a dip in the Atlantic Ocean and her witnesses were 3 female friends.
When I asked her if I could help her by arranging for her to go through a kosher conversion and mikvah, she said no thanks, religion is in your heart.

It was only after finding the above quote about 'zera kodesh' do I understand why the Rebbe instructed MN to convert me ASAP.
So I'm wondering if a man has gone thru 'karet' and his child converts, does that help his neshoma at all?