Jack Antonoff Uses Music to Cope with the Loss of Teen Sister 15 Years After She Died of Brain Cancer

While Jack Antonoff is a proponent of therapy, he’s found songwriting is just as healthy a way to process his emotions.

On his band Bleachers‘ sophomore album Gone Now, the singer addresses a number of life experiences, including the death of his younger sister Sarah, who succumbed to cancer at age 13. (His older sister, now 36, is the noted fashion designer Rachel Antonoff.)

“Songwriting can be this tool to connect with people and talk about what you are going through,” Antonoff, 33, says in the new issue of PEOPLE. “There’s two parts of: the part that moves forward and the part that’s frozen. It’s very much a then versus now. For me, it’s 18 and younger, when my sister was alive.”

Adds Antonoff: “I used to write from a very lonely place, like, ‘Here’s my story, this is it.’ Now I’m writing from a place, like: ‘Well, everybody has that! Everybody’s got a then and now, and everybody’s trying to figure out how you not let go of the then but also not compromise the now.’ That’s the whole push and pull of this album.”

The former fun. guitarist has said he has lived with anxiety and depression in the years since his sister died. He examines pain and grief through a universal lens on Bleachers’ nostalgic, ’80s-tinged new LP, particularly on standouts like “Everybody Lost Somebody.”

“I talk a lot about loss,” says the pop-rocker, who is dating Lena Dunham, 31. “Most of the stories that I talk about are 12 years old. Why am I still talking about them? How does that affect me now? It’s time to figure it out; it’s time to tell my story — who I used to be, who I want to be — and move on.”

In addition to his success with both fun. and Bleachers, Antonoff has become a go-to songwriter and producer in the pop world. He’s helped craft earworm hooks for everyone from Sara Bareilles to Carly Rae Jepsen, contributed three songs to to pal Taylor Swift‘s Album of the Year winner 1989 and — most recently — cowrote and coproduced Lorde‘s superb second album Melodrama.

For more on Jack Antonoff and Bleachers’ new album, pick up the latest issue of PEOPLE, on newsstands everywhere Friday.

So what’s his secret?

“We only need to write songs about the things that we’re going through that are things that people can connect with,” says Antonoff. “You can feel less alone — at least that’s why I’ve always written songs. I see them as sending out a letter with a bird, and then you write it, and it takes forever, and all of a sudden, someone at the other end of the world is like, ‘I feel that way, too! I agree!’ And I’ve always been lucky to meet people who feel the same way about songwriting.”