Ask HN: Book recommendations for helping partner heal from child abuse

I am in a (platonic) relationship with someone who suffered abuse as a child.

We're slowly working through things together which is absolutely fantastic, but I feel woefully inadequate at counseling and also it's hard if not impossible to be truly objective.

I have offered to pay for therapy but he/she is reluctant to accept such an expensive gift. It's affordable for me on my programmer wages but impossible for someone in with no income and limited support from the welfare system.

We have a complicated relationship that flickers between me as a love interest and me as a (primary?) care giver - something I am fine with but he/she struggles with as it conjures feelings of inadequacy which I then have to quell.

Can anyone on HN help with book recommendations ? Anything that will help me empathize better, be a better listener, and deal with the emotional turmoil that happens on a semi regular basis.