Talk to Pediatrician on Speaking Problem

Hi, my son is 2 years and 5 months, weighted 13.5 kg. He doesn't speak a single word, just points towards his demands, but he is very intelligent, spells alphabets and sings peoms very well. He doesn't play with any child or in group rather goes in isolation. He doesn't respond his name, nor does he play with all toys, except his alphabet blocks. He cries silently while sleeping. He doesn't like to be in crowd rather loves living in his own home. I researched about Autism, very few points go in his favor not all. Now a days he also close his ears even if there is no noice. His eye contact and confidence level is zero ( family problem). Im worried too about his diet, he resists every new thing while prefer to eat the tasted stuffs. Whom should i consult, and how to cope the situation. ( Things got worse after my 2nd baby born).