My son is starting to ask questions about his special needs sibling

My son, Liam, has started asking more questions about why his sister behaves differently from his friends. I knew this time would come, when I’d have to start answering the “why” questions.

My daughter, Liv, has Sanfilippo syndrome, a neurodegenerative genetic disorder. She is 6 years old, but her cognitive abilities are those of a 9- to 12-month-old. She doesn’t understand danger or right versus wrong. Liam is 4 and has recently started getting frustrated with his sister. “Why is she doing that? How come she gets to do that, but I don’t?”

Liv is nonverbal and doesn’t play pretend, sit down and color, or make magnetic tile towers. She chews on toys, throws things, knocks over Liam’s towers, and occasionally takes a gentle swing at him. He’s always been a very patient brother, but lately it’s starting to get to him.

Recommended Reading

Aug. 24, 2026 News by Steve Bryson, PhD

Groups invest $5.5M to expand access to experimental Sanfilippo B drug

Liam hugs his big sister, Liv. (Courtesy of Erin Stoop)

I used to tell Liam that Liv was still learning, but that isn’t holding up like it used to. He understands now that she’s older and thinks she should know better. I’ve started saying, “Her brain doesn’t work the same way that yours does. She doesn’t understand that what she’s doing is wrong.” That’s a lot for a 4-year-old to take in.

Even though he is still confused about why she’s different, he’s become more compassionate and patient with her. When someone got frustrated after Liv chaotically grabbed a glass dish from the counter, Liam immediately stuck up for his sister, saying, “Liv doesn’t know any better.” It hurt my heart to know he was right, but I was proud of him at the same time.

Only recently have I started telling him that Liv has Sanfilippo syndrome, and that it’s not her fault. I tell him she was born that way, and we love her regardless. Liam has yet to question it beyond that, for which I’m grateful.

Liv, Liam, and Erin Stoop enjoy a summer afternoon outside. (Courtesy of Erin Stoop)

I do fear the day when Liam wants to know more about her disease. I don’t want him to find out from a friend at school that his sister is dying. I want to be the one to have that tough conversation with him when the time is right.

My guess is that it’ll come in stages. We can start by talking about why she gets sick more frequently, needs more medicine, and goes to the doctor more often. The harder challenges lie in the years ahead, if she loses her ability to eat by mouth, can no longer walk, and starts having seizures. At that point, we may not be able to sugarcoat things.

My hope is that I’ll know when the time is right and that I’ll use the right words. I want Liam to look back at his childhood and remember his time with Liv fondly. I do not want him to feel like a glass child or think we weren’t honest enough with him.

I know that having a sibling with special needs often causes a child to grow up quickly, but I don’t want to take Liam’s carefree years away from him. He truly is an amazing kid and a loving brother to Liv.

Note: Sanfilippo News is strictly a news and information website about the syndrome. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The opinions expressed in this column are not those of Sanfilippo News or its parent company, Bionews, and are intended to spark discussion about issues pertaining to Sanfilippo syndrome.