Hi uglymug and Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work There is no problem with filling in your answers on a separate, typed, sheet and attaching it to the back of the form. Clearly indicate which question you are responding to. Don't forget to number the pages at the bottom of each sheet (we suggest '1 of 11' etc as this makes it clear if pages are missing from the end) and put the claimant's name and NiNo at the top.
You should then write 'see additional page 3' etc in each text box relating to the questions. You might also want to provide an index at the front of the pages.
You might like to bookmark/favourite this on your web browser now so that you can find it easily in future. This will allow you to return with further questions/comments about your friend's PIP claim without having to start a new topic each time. It helps us enormously when everything relating to the same claim is kept in one place - and I hope you will find it useful too