Correction needed: Malka Tabak was not Meyer's mother. It may have been Lee (Leah??) but I have no confirmation,
Malka was Shlomo Shimen's second wife, mother of my grandfather Gedaila (George) Tabak who arrived at Ellis Island in Jan 2021 with Gedalia's wife Rachel, daughter Sonia, and his mother Malka (misspelled as "Matka" on the ship manifest.
The posthumous biography of Meyer Tabak ("Meyer Tabak: His Life and Times" published around 1948) gives info, but only a sentence or two about Shlomo Shimen re-marrying and having a son and several daughters. So Meyer,, Herschel/Harris, Yankel/Louis etc were half brothers to Gedaila (George)
And the family tree is confusing because Meyer and his wife Minnie were cousins, I believe first cousins (which was not uncommon at the time,((
Robert T