Hi irisheyes,
The title of your post uses the word appointee. Do I assume correctly that you have applied to DWP to be an official appointee? If so then as appointee you have the same powers as the claimant, here your daughter. This means signing forms, answering calls and potentially attending an assessment although I am aware of the assessors not really liking that! Also, and crucially you can speak at a tribunal.
If you are not an official appointee, then you can still attend the tribunal and speak on your daughter's behalf as a representative. The rules also allow that as rep. you can also give evidence too. If there are others who would wish to give evidence they too can attend at the hearing and give evidence as appropriate.
Either as rep and or appointee it is likely to be an error of law if you are not allowed to speak and or give evidence.(This would mean that the decision of the Tribunal could be appealed if the decision went against you.)
If your daughter was previously on PIP or DLA then it is important to make sure that the tribunal has full details of the previous award. If DWP hasn't sent the details, and you have the papers, you should send these in.
Make sure you send the sectioning details and any psychiatric reports to the tribunal. The tribunal maybe will insist on a further adjournment for your daughter to appear. Unless it is clear that your daughter will be out if hospital in the very near future the danger is that even next time the hearing might still need to be adjourned if daughter is still on section. Who knows! If either appointee OR rep is present at a hearing then the appellant is deemed present. You have had 2 failed hearings, and since no one knows when your daughter will be home, let alone fit enough to attend, there should be no reason to delay again, unless there is something else very compelling. Be prepared to resist a further adjournment.
Please note, if your daughter stays over 1 mth in hospital this can affect PIP. (It will depend on whether she gets daily living or mobility, and exactly what sort of establishment she is in. ) This will only affect actual payment, not the underlying entitlement. Once your daughter is out of hospital then she can receive full payment. There may consequently be deductions from any back dated payments which will be adjusted to reflect longer stays in hospital.
I hope this helps.
LL26
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
