Not related to the dwp but have you asked about patch based medication?
I have Buprenorphine patches for pain relief 5cm x 5cm plaster that stays on for 7 days & painkillers are passed direct thru the skin into the blood. It bypasses all the digestive issues and eliminates the ups/downs of pills as they wear off, forget to take them etc they’ve really helped me out. I have 25 microgram patches they do smaller ones at lower doses too.
Just might be if help to you if you ask the Dr about them.