About this deal
You will probably find most of these items in your home already to make a great little homemade costume. A child caring for their parent (typically a mother) suffering from dementia has been done far better in horror before. This movie makes me think of a film like The Taking of Deborah Logan. Family conflict horror dramas are a popular subgenre right now (e.g., Hereditary), but like any trend, there are highs and lows. This is definitely a low. Then run the colored ribbon or string in and out the holes leaving enough on both ends to tie a bow once the child is in the pillow case.
White pillow case - could be standard, or king, even european style depending on the size of your child This could be used for any age child, you'll just need to change the size of the pillowcase you use for the size of the child.