Kevin Federline, his mother Julie Bleak, and Lynne Spears have reportedly been caring for Sean Preston, 17 months, and Jayden James, 5 months during Britney’s recent rehab stints. The once popular teen queen is rumored to be “on the run.”

“He is beyond sad,” says a pal of Kev’s. “This is the worst week of his entire life. He doesn’t even want to pick up the phone. Things are beyond not well with Britney, and he still loves her.”

K-Fed made a call to his mother, Julie Bleak, on Valentine’s Day asking for her to help him take care of the children.

“Britney’s family feels that Kevin has been a blessing and they are very impressed with Kevin taking so much responsibility,” says a Spears family source. “Britney’s family found out from the news this morning that Britney had left the rehab. Britney has not asked to see the kids because she knows she is not well and she does not want to scare Preston. She has no credit cards or cash. She is basically on the run at the moment.”