Some disabled young people, or their appointee, can claim UC whilst in full-time education in a limited number of situations. They need to be in receipt of PIP.
For those claiming before the September following their 19th birthday, LCW/LCWRA needs to be established prior to the start of the course. This is done via a credits only new-style ESA claim.
From the September following the young person’s 19th birthday, the rules are different for those in non-advanced education. LCWRA doesn’t necessarily need to be established prior to the start of the course, you would just need to prove the course is not incompatible with any work related requirements on DC’s individual claim (which may be none due to disability). However, it is still worthwhile making a credits only new-style ESA claim now.
For the full picture, those claiming following the young person’s 19th birthday who are in advanced education also need to establish LCW/LCWRA prior to the start of the course.
Contact has information about UC and young people here and here.
DC will only be a qualifying young person on your UC claim up to and including the 31st September following their 19th birthday. It cannot continue until 20 unless they happen to have their birthday then too.
Have you had social care assessments? An assessment of DC’s needs and a carer’s assessment for you. Depending on their needs, if you haven’t already, you might want to look at CHC funding too.