There’s an appealing sincerity to the work of Abigail and Shaun Bengson, a married indie folk duo with a genial stage presence that they’ve applied to stage works in which they’ve also performed. The Bengsons’ latest concert piece, The Keep Going Songs, which opened Thursday at the upstairs Claire Tow space at Lincoln Center Theater, is a musical exploration of the grief we carry and the ways in which we cope with loss. There’s a genuine poignancy to the material, much of it written in the wake of the sudden death of Abigail’s older brother, a childhood cancer survivor who succumbed to the disease last summer in Boston while the couple were touring in San Francisco.

Loss hangs over the the loosely structured program, which features musical and spoken-word digressions about the wonders of the natural world. (Did you know whales and dolphins evolved from land animals before returning to the sea?) Mostly, their show demonstrates the struggle of middle-aged creatives wondering if their lives and livelihood are still sustainable in the current economic climate — and of finding meaning in the absence of a traditional religious belief system. They mention peers who have gone on to bigger success as well as the challenges of raising two young kids in New York City while also looking after an aged parent.

Perseverance is not only a theme of the loosely structured program but also a prerequisite for the audience. At just under two hours, this concert can be a long sit — marred by some meandering monologues between songs and some truly bizarre moments, like Shaun donning a single crab-leg puppet arm and performing a choreographed crustacean routine. (Director Caitlin Sullivan directs the production, on a set by Cate McCrea that features lots of recycled elements from past Lincoln Center productions, like curtains from The King and I.) The Bengsons’ act sometimes suggests a more polished, hippie version of Bobbi and Marty Culp, the overly earnest and somewhat out-of-touch middle school music teachers played by Ana Gasteyer and Will Ferrell on SNL back in the day.

Musically, the Bengsons have obvious skills. Abigail’s voice has an alt-rock edge to it, but she also can flip up into her upper registers with the fluidity of a trained opera singer; while Shaun’s quick-fingered work on the acoustic guitar overshadows his more workmanlike baritone. But there’s a bit of sameyness to the songs, which fall comfortably into the guitar-based folk idiom, with the addition of synthesized drum beats and live production of overlapping vocal tracks to create instant harmonies.