Once the ankle has been immobilized with the pillow, re-assess the function of the foot below the injured ankle. Note any differences between the first and second assessments.
A pillow splint will provide enough support for an injured ankle to get the patient to medical care. A pillow splint is not a long-term solution. This is just enough to get to a healthcare professional.
You can still ice an injured ankle once it has been splinted. Just be sure to put the ice pack over the pillow, not under it. Believe it or not, you can easily cause frostbite with an ice pack.