My child has poor motor control, can’t walk or stand and the doctor diagnosed him with kernicterus. Could it have been prevented?

Whether your child's kernicterus could have been prevented depends entirely on the circumstances surrounding your child's birth and the treatment they received in the neonatal period following birth.  You'd need to review the medical records to know whether the condition could have been avoided.  It is possible kernicterus is what led to your child's deficits.