Japanese to English Social Sciences History

Another question about the history paper I'm currently working on (sorry for asking two questions at once).

This comes up in a kind of diary entry by a woman who married a disabled returnee who had lost his arm(s). She is talking about how hard it is to live with the man after she married him. I will give some context below.

そのことについて彼女は次のように書いている。「それで夜は心棒だそうです。酒の力を借りて、酔っている内に床に就きますが、夜中一眠りすると又痛み出して、何度も寝返りをして、時には癇癪を起こして、私に当たり散らします....

I know the basic meaning of 心棒, so I'm not looking to be pointed toward an online dictionary. What I don't understand is what the woman means by using it in this context.

Thanks again,

Nick