Progress? I don't see his apology as progress at all. Progress means changed behaviour. He shows no inclination of doing so whatsoever.

I am sorry but mental illness does not mean one gets a free pass. There is accountability which, again, he is not taking.

I don't understand why you are still prioritising him and/or making excuses (i.e. his mental illness, his apology, his 'progress') when your daughter is telling you explicitly how she is feeling about this dynamic. She is already suffering. All that this 'teaching' her is that being with an abusive partner is okay. It is not!