I can get somewhat close from the Census Person Income in 2017 all data tables:

https://www.census.gov/data/tables/time-series/demo/income-p...

That has numbers of people in $2500 income intervals. Calculate people in interval * 1/(income/minutes per year) for each interval sum and divide by total with income and I get an average poverty of 49 minutes.

I think he might be using after tax income and may be calculating based on household income/household members or similar instead which would explain the discrepancy (since children don't work).