After 28 weeks in hospital

My partner was on DLA (mid-rate Care and high rate mobility). March last year was put on PIP (standard for each). Less than 4 weeks later he went into hospital, where he spent 7 weeks in Chesterfield hospital then 21 weeks in Queen's Medical in Nottingham. He had MS, asthma, peripheral vascular disease and trigeminal neuralgia before going into hospital. He now is on Total Parenteral Nutrition fed through a Hickman line into his heart after having all but 15cm of his small intestine removed for the rest of his life. He also has 2 stomas. He also has depression. We informed DWP that he was in hospital and told them when he came out. They sent a further PIP application form, but didn't re-start his previous PIP payments. They received the completed form on 24 Oct 2017. He was interviewed at home on 13 January 2018 and yesterday received a letter giving him standard care and mobility, although his health is so bad now he is finding it hard to cope. He has to have help to attach himself to the daily 5 or 3.5 litre drip and remains on that for 18 or 20 hours every day. I feel we should appeal this decision - am I right? Any help would be appreciated.