If Jetblue is late, she is taking a risk being stuck in a security line and missing her flight.

Tell your sister to pack lightly enough that she travels with carry-on only. She can't waste time at the baggage carousel at T5.

Also, when she takes the Airtrain to T4, tell her to make sure gets on the Airtrain whose first stop after T5 is T4. Scroll to the bottom to see map: https://www.panynj.gov/airports/pdf/...re-english.pdf

To piggyback off Often1, she is NOT connecting at JFK and has none of the protections that a connecting flight offers. She has 2 separate tickets.