Sounds like her grandfather needs a nice heavy mouse. She could disassemble a modern mouse and add lead weights to the inside until the weight and balance were right.
A touchpad on a laptop is less ergonomic than a mouse on a properly arranged desktop. But a touchpad on a laptop is more ergonomic than a mouse on a laptop unless you set up your laptop like a desktop (place it on a stand on a big, clear desk with an external keyboard in front and a mouse pad to the side). Trying to use a mouse with a laptop that is sitting on your lap is, in my experience, invariably awkward.
