hlmencken3 said: One’s essential Jewishness is retained forever.
A Jew who ‘converts’ to Christianity may forfeit some treatment as a Jew (such as being buried in a Jewish cemetery), but need not convert to Judaism should he return to Torah observance. If female, her children will be Jewish.
**you can’t just make up your own Jewish law! Her children will absolutely NOT BE JEWISH. She is done with Judaism.
Please consult an Orthodox rabbi.