She is parentifying your daughter. Man. Plus, i think your daughter needs to be protected from her cycles, not get her hopes up that everything will be okay from now on. Its not a matter of betraying brother.

I wanna see her stay away until she has 90 days sober and 90 AA meetings in 90 days. I feel so bad for your daughter. The sins of the father are visited upon the children. She will have your same hopes.