hello Florine
a warm welcome to TP
your aunt and uncle are fortunate to have you looking out for them both
I agree with Beate - get onto their Local Authority Adult Services and say they both need an urgent assessment of care needs, and your uncle is entitled to a carer's assessment as well - tell them you fear that your uncle is close to 'carer breakdown' and needs support to care for his wife so she can stay at home - use the buzz words Beate mentions = 'vulnerable adults', 'at risk', the 'duty of care' lies with the LA
your aunt's care will be funded only from HER finances (same for your uncle) - if she has savings/assets (not including the house) below £23000 the LA will at least partly pay any fees - if the LA ask about her finances, say you don't know the situation as some seem to be trying to get away from doing the assessment by finding out that a person is self funding - your aunt has a statutory right to this assessment
do let your uncle know that he will not be required to even consider selling their home to pay for any care for his wife - some people are afraid this will happen
also have their GP given an up to date picture of how things are for the both of them, as the GP can make a referral to Adult Services too
I hope your aunt is receiving Attendance Allowance and the Council Tax has been reduced so that your uncle only pays as the single person's rate - helps a little with any care fees
have a chat with Admiral Nurses too
https://www.dementiauk.org/how-we-help/admiral-nursing/
and, now you've found TP. keep posting
best wishes