Dear Ella,
You're in the same boat that many of us have been in too. I know the heart break you're feeling right now and also the feeling of helplessness. I'm sure like me, you also have this overwhelming urge to step in and take control and responsibility for your parents, but in reality, it isn't as simple as that.
Although I knew Mum had Alzhiemers, my Mum and Dad seemed to be coping, although I was aware the house duties were being neglected and their clothes were sometimes grubby. When I visited I would discretely do abit of cleaning, put a wash on, etc. If I was caught, I'd be told that mum would do that later! Of course she wouldn't.......
My Dad coped with Mum really well, He would bath her, it wasn't as often as it should have been because she was always convinced she'd already had a wash that morning! He cooked her meals and did a great job. In fact, He did such a good job, I didn't realise how bad mum was getting.
I'm just trying to explain to you that I'm sure your dad has been hiding just how bad your mum has become and when you went to see them, it came as a shock to see the change in her. I would try to have a frank conversation with your dad and reassure him that you want to support him as much as you can, but you need to now exactly how your mum is behaving. Ask him if he thinks there has been a change in her since the medication was started. Maybe she has been been behaving like you described for a while and that's why she's been put on the medication. I know from experience that my mum would talk to me on the phone and she would appear fine. It was almost like she went through all the pleasantries, almost like a robot. Although I didn't realize that at the time, only when I looked back.
Sadly, because you live far away, and cannot see your parents as often as you'd like, the changes will always be more obvious to you. You really can't get a true picture from speaking to your mum on the phone and I'm sure because your dad doesn't want to worry you, he may not be as truthful as you'd like him to be.
It would be helpful to try and talk or write a letter to your mothers doctor explaining your concerns and giving them your contact number. I would regularly update my parents doctor on how things were for both of them and although he never told them of our contact during the bad times he could appear to randomly phone dad and ask if he could call in to visit mum and then sort out problems. My dad never wanted to bother the doctor!.......
I'm thinking of you in this heartbreaking situation, and I know it's very hard, but it's the illness that is making your mum behave the way she is. She really doesn't mean all of the horrible things she says to you...
Jane x