Any way you slice it, rehab is serious stuff. But Billie Joe Armstrong's current trip to an undisclosed facility to deal with unspecified substance abuse issues may be way more serious than it seemed, as Green Day bandmate Mike Dirnt has come out to say that Billie's "life is in danger."

In a new Kerrang magazine cover story with the tagline "How A Rock Opera Saved Mike, Tre and Billie Joe," bassist Dirnt discusses Armstrong's rehab stint at length. "Billie doesn't take things lightly and he wouldn't take rehab lightly, either," says Dirnt, according to the NME. "He's in the middle of some really big things, but we're going to pull through. It's killing everyone. Green Day has never been a band that sits still, but sometimes you have to step back and let life go on rather than try to control everything."

Armstrong was shipped off to rehab last month following an onstage meltdown during the iHeartRadio festival in Las Vegas, during which he taunted concert organizers with a profanity-filled rant and smashed his guitar before sauntering off stage. A band insider later called his rehab stint long overdue.

Green Day have since cancelled their Oct. 27  slot on the bill of the Voodoo Music + Art Experience in New Orleans, and the status of the band's upcoming North American arena tour remains up in the air. "We're brothers-in-arms waiting for Billie to return healthy, but we're not going to force anything," adds Dirnt. "[Drummer] Tre and I will be standing here for Billie."