Wow 100 years old! God bless him. I help sit my mother upright at a 90 degree angle with a fluffy pillow under her head, due to aspiration precautions for her meals. I put pillows on both sides. This keeps her upright and she does not drift to the side. My mom will be 98 in the Fall, amazing generation, isn't it? Maybe PT can advice you. I have called PT at my moms hospital for over the phone advice in the past on equipment. Hope you find a good solution. Give a great big hug to your dad for me.
