help me

[Farzana]

My 3 years old boy was normal at birth. He got meningitis at the age of 40 days and remain on ventilator for 06 days.After that he got genetralized Hypotonia.He can do only flickering movements of his hands and some eye movements.He can't suck feeder. his CT bain at the age of 9 month show prominent sulci & gyri. His NCS, EMG and muscle biopsy was unremarkable at age of 10 months. However with the passage of time this bilateral & symmetrical hypotonia is getting improved. Now condition is that he can sit with some left sided functional scoliosis.His right arm has better motor activity than left arm.He can grip. hold the pencil & draw lines on paper with right hand, but cant take his right arm above the head. And left leg is much better with all movements power 4.but right leg is very weak feeling some movement on right hip joint ans right Knee flexion and toes only.he is also developing right foot drop deformity with outward rotation of the right leg, right knee is turning toward inside.Can EMS is helpfull for his floppy muscles?.He can't bear weight on his legs yet. But He is crawling (while in sitting position he propel himself forward moving on his buttocks and can reach to the desired place).I am doing passive ROM of all joints. Now I need help for strenthening exercises for his left sided functional scoliosis and right leg. I am doing some swiss ball exercise for back strengthening also.kindly give more details about swiss ball exercises as well as strengthening & balancing exercises.
I am attaching some images of my child.