Hey Trampledon,

I think if your Partner is in denial which is a clear yes, and her Mum is also in denial saying she is fine which is also a clear yes then maybe you have to step in and say no everything isn't fine and if that means you going to her Doctor's then so be it. Do you think you can chat to the teenager about her Mum's behaviour? Maybe this is an alternative speaking to the teenager and letting her tell you about her Mum's behaviour.

Sometimes if we are far gone like your Partner is we need oour loved ones to tell us that we are not well and need intervention ie meds, doctors, hospital etc.

Hope this kinda helps