I can think of many best selling memoirs with starkly honest retellings of hard lived, difficult lives.

A Hole in the World (Richard Rhodes)

Wasted (Marya Hornbacker)

Dry (Augusten Burroughs)

Rhodes is a Pulitzer Prize Winner, although not for his memoir. His memoir details his boyhood raised by his clueless, neglectful father and a step-mother so evil you wish she was Cruella Deville.

Wasted is Hornbacker’s memoir of Anorexia. It is honest, brutal and devastatingly (wonderfully) written.

Dry is Burroughs telling of his journey through alcoholism and drug addiction and his relapses and the death of one of his best friends as a result of AIDS.

Good writing overcomes a story that is difficult to hear about.

Your beta reader sounds like someone looking for some other kind of memoir.