During this age if a child is not moving his legs on his own then it is recommended to do some exercise, especially gentle stretching with the child. 1 to 3 years
“This is the age at which the characteristics of diplegia become more noticeable, mainly because, unlike other children at this age, the child with diplegia is not walking.”  By the age of three, it is important for the child to be in a specialized school environment so the child can participate in physical therapy and learn social skills. Parents should not force the child to sit, crawl, or walk a certain way during this age period. Let the child do whats comfortable for them and allow the therapist to correct this problem. If you want to help your child walk more, then push toys are recommended for walking aids. Regular exams should be done to make sure the childs legs are growing normally and he or she is not having any problems with the hip. 4 to 6 years
“This is the age range at which the child with diplegia makes the most significant physical improvement in motor function.”  During this time period the child makes major improvements in motor function. He or she should be in a regular school and focus on cognitive issues not therapy. A child using a walking aid for mobility to move around with the other children is not a bad thing.
Diplegia, when used singularly, refers to paralysis affecting symmetrical parts of the body. This is different from hemiplegia which refers to spasticity restricted to one side of the body, paraplegia which refers to paralysis restricted to the legs and hip, and quadriplegia which requires the involvement of all four limbs but not necessarily symmetrical. Diplegia is the most common cause of crippling in children, specifically in children with cerebral palsy. Other causes may be due to injury of the spinal cord. There is no set course of progression for people with diplegia. Symptoms may get worse but the neurological part does not change. The primary parts of the brain that are affected by diplegia are the ventricles, fluid filled compartments in the brain, and the wiring from the center of the brain to the cerebral cortex. There is also usually some degeneration of the cerebral neurons, as well as problems in the upper motor neuron system. The term diplegia can refer to any bodily area, such as the face, arms, or legs. Facial diplegia
Facial diplegia refers to people with paralysis of both sides of their face. Bilateral occurs when the onset of the second side occurs within one month of the onset of the first side. Facial diplegia occurs in 50% of patients with Guillain–Barré syndrome. Facioscapulohumeral muscular dystrophy (FSHD) is the second most common adult-onset muscular dystrophy with facial weakness being a distinct feature of FSHD in over 90% of cases.