Rick Hilton tells Usmagazine.com - the half-hour visit - between bullet-proof glass at the visitor's center inside L.A.'s Twin Towers Correctional Facility - was "hard."

"She's weepy," Rick says, "but she's doing the best she can. It's hard, but she's hanging in there."

Meanwhile, Kathy Hilton told TMZ reporters: "It is what it is. [Paris] wants to just do her time, and get on."

In other news, Paris Hilton has lost her agent. Usmagazine.com has learned that the incarcerated heiress, who once had a team of agents at the Endeavor Agency, was dropped this week because Hilton "just wasn't worth it," an agency source tells Us.

A rep for Endeavor said "Paris is no longer a client."