ex-felon, [with] a baby daughter he never sees and an alcohol problem and a drug addiction, who is harrassing and/or stalking your friend.

"Over-reacting" might be buying a gun and never leaving the house.

Getting a new phone number or blocking his texts is not over-reacting to someone who is a felon with addiction issues and has clearly indicated he's obsessed with her. If he's sending her texts, he's probably also driving past your dorm/apartment and following her when he can.

Seriously: The Gift of Fear. Get her a copy.

There is no shame in taking care of your own safety, and she might want to consider that she's also putting you and your suitemates at risk by her refusal to take action. (My sophomore year in college, a stalker showed up and took the object of his obsession and her roommate hostage before shooting and killing them both.)