Talk to Pediatrician on Child Development

My daughter will be a year old in ten days iA.. She started sitying unsupported for a min or so by 6 months plus and gradually was sitting well without support be 8.5 to nine months for a prettt prolonged period of time, she still cannot come into a sitting position from a lying down position all by herslef needs slight support like i have to hold her legs lightly so that she can pull up. Recognizes her name her own enviornment, overall she is a very happy baby. She cannot crawl or stand up on her own.. If i make her stand with support she starts crying after two to three minutes. I have an older son who has global developmental delay due to arrested communicating hydrocephalus. Now im really worried for my daughter since i guess her milestones are also slightly delayed. I have consulted a few drs and they say she is going on fine and not delayed. Please help me how to help her achieve her milestones within range