Does this sound like down syndrome?

My best friend's mother had another child when she was in her mid 40s. The child will be 4 next month and I am very concerned. The little girl has a limited vocabulary and can only say words like "pizza or hi." She also still wears diapers and drinks from a bottle. When the woman was pregnant, the doctor suggested that the child might have down syndrome and wanted to do an amniocentesis, but the woman refused. It concerns me because she has yet to seek professional help for the little girl. She also cries continuously over anything and everything. I have never had kids so any advice would be greatly appreciated. Thanks.