My grandson is three and half years. He is absolutely normal health wise. He goes to play school and seems to enjoy. He utters words like Amma appa ayyappa. But is not coming out with sentences. Vocabulary is limited. Very cheerful active playful. Some say he has mild Autism. For three months he went through some sort of speech therapy. Slight improvement was found. Eye contact is there. Some times he does tow walking. Beta tests are negative. What could we do? Any advice?