Hi bikerdave5
The DWP typically send out review forms up to a year before the award end date to give themselves plenty of time to process them, so the timing is not unusual and is unlikely to have been triggered by your partner claiming Carers Allowance.
I would read through the guide to PIP claims and reviews for the latest information about filling out the review form. You can only send in what information you have, and I would try not to be overly concerned that you have no new medical evidence. Many people are in a similar position. People have different approaches to filling in the form - some people rely on them reading past information - others prefer to repeat a lot as if it's the first time they have told them. So much depends on how people are feeling at the time of completing the form. Just never assume that the person reading your form, understands all about your condition and how it affects you.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems