I call all my older brothers and sisters ate (older sister) and kuya (older brother). My parents really did not have any opinion about this, but we had an older au pair from Lipa who strongly believed that younger siblings should call older siblings ate and kuya out of respect. We only needed her services for a short time, but I really listened to her.
I don’t think my parents cared with labels, or they would not have waited for the au pair to teach me to call my siblings ate and kuya. It seemed to me that what was more important to them was the love and respect that each of their children had for each other, regardless of birth order! In our own household, we use something similar to ate and kuya. My daughter calls her older brother ahia (Fookien for older brother). My son calls his younger sister shobe (Fookien for younger sister).
Beyond the labels, I aspire for my children to grow up respecting and caring for each other and the family. To start, we divide household chores equally between the two—folding laundry, putting away dishes, putting away toys, tidying up their bedroom, and a whole lot more. It would be very easy to give in to the younger one’s request to let ahia do it because he is bigger, but we don’t. Sometimes it would be simpler if the grown-ups did everything, but we don’t. To me, being responsible for certain things in the house shows that each person respects and cares for the family. In my opinion that show of respect is more heartfelt than simply calling someone kuya and ate.
I have to admit though that it is cute to hear my children call each other ahi (short for ahia) and shobes (short for shobe). Especially if the tone used is exasperation bordering on rage. Like, “Ahiiiiyaaaaa, let me play with your green army soldiers!”