Hi
@Lubey
Welcome to the forum. Sorry to read about your mum.
It's v common for a PWD in early stages to be in denial and not to admit anything is wrong, and if they do realise something is wrong, then as it's not them, it must someone else - usually OH gets the blame and the flack.
You haven't said how old your mum and dad are, as that can make a difference in coping with this terrible condition and its deterioration.
As you said you are part of a big family, then hopefully several members make take on some of the caring tasks, time etc, so it doesn't all fall on your dad. Eg, one of my sons comes every Thurs evening so I can go and play bridge as a break from the caring. Breaks for the main carer are v necessary to retain sanity, speak with other people/adults/ etc.
When someone is in denial, it's not uncommon for someone - such as you or your dad - to write down the situation, yours concerns, etc and then speak with the PWD's GP or to write to the GP and get the GP, if possible to require your mum to attend a "well woman " clinic / chat and then the GP can see the problems and suggest medication if necessary, or make referrals to the memory clinic or the Local Authority Adult Social Services team,
Best wishes
