Hello @MJBairn and a warm welcome to the forum community.
I am sorry to hear about your dad’s problems with medication. I see Jane_L has already offered some helpful information and I’m sure some more of our helpful members will be along to offer information and share their experiences soon.
In the meantime have you tried the Parkinson’s uk shop? https://shop.parkinsons.org.uk/ They stock a whole range of daily living aids for people with Parkinson’s and they may have something suitable to meet your dad’s needs.
Alternatively our helpline advisers may have more information or helpful suggestions. Our helpline is free and confidential and our advisers can answer questions and provide support on all aspects of life with Parkinsons. We are open Monday-Friday 9am-7pm and Saturday 9am - 2pm (closed Sundays and Bank holidays). You can contact our helpline on 0808 800 0303 or at [email protected]