What Are The Symptoms Of Autism In A Child?

My grandson just turned one and is unable to sit independently, has just started to army crawl, babbles a little, and vomits a lot. He has been seen by a GI specialist who feels that he will stop vomiting as he gains more muscle. He has been diagnosed as floppy tone. This week his pediatrician became concerned about autism since he is so delayed. What do you think?