Sounds like autism to me... I have two autism boys it's hard but I love them to pieces
I am sorry to hear about your son. Often, the cause of a delayed milestone cannot be ascertained. It may be premature birth, autism, cerebral palsy, recurrent ear infections, or Down’s syndrome. I know it is difficult to wait for the results—but hopefully you will know the cause. A genetic association may be there since your elder one also has developmental delay. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.