"If these clots got to her major organs, it is all over," he said on Facebook.
Miss Wilson was also due for a second operation on her pelvis yesterday.
The three to four-hour spinal surgery to reattach the base of her skull to her spine, which was originally scheduled for Wednesday, was due to be performed today.
It was originally delayed because of a technical issue with a major piece of equipment needed for the operation. The procedure would leave her with permanent restricted movement of her head.
Miss Wilson was born with Crouzon's Syndrome, a condition that meant the bones of her skull were fused together.
Timeline
*Sunday 2.10am: The car Diane Wilson was driving is involved in a three-car crash in Melbourne.
*Monday: Family from New Zealand and Perth flew in to be at her side.
*Tuesday: A CT scan showed no new damage had occurred since the accident.
*Wednesday: Scheduled spinal surgery was delayed.
*Thursday: She underwent operations to insert a blood filter and start to repair her smashed pelvis.