pip appeal

hi everyone i'm unsure if im at the right place but my husband as lodged an appeal for pip .he was on dla for approx 20 years had several f2f and won is award back is last f2f he failed to score any points at all .we asked for mr still no points.we have seen is mental health dr and he is writing a stern letter. about is diagnosis medication and that he could have a relapse at any time etc .what do i do with the letter do i send it to the appeal or do i hand it in on the day of the appeal . bare in mind i telephoned the appeal office yesterday and it stated it could be up to 60 weeks before the appeal is heard . and do the dwp get a copy of the letter and could they change the decision before appeal is heard .thank you