I did not look at the English part of the stone earlier, so I now want to point out that there is a discrepancy of 2-3 days between the Hebrew and the secular dates.
If the 5th of December is correct, then the equivalent Hebrew dates are the 2nd of Tevet (if he died before sunset) and the 3rd of Tevet (if he died after sunset).
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Fredel Fruhman
Brooklyn, New York, USA