This children has Knee valgus and pronated feet. To avoid the further deformity of Knee and foot arch. Some suggestion are given:
Choose shoe with foot control function which mean having a rigid heel cup. It can reduce the degree of heel and knee valgus
Doing exercise to train up the foot muscle for supporting the foot arch and encourage bone growth. We advice him to do tip-toe standing and toe griping exercise
With arch support insole to life up the arch.