Suggest Treatment For Adult With Under Developed Brain

aoa,dear doctor my sister is 23 years old. her brain is not work, her brain is two years baby, she understand what we say.she likes cricket match. some doctors says her muslez not work,when we hold her hand she pulled back,she crying very loudly at 1 or 2 hours.she beat us when she is loosetamper.plzzzzzzzzzz tell me what we do