8 years old and doesn't sleep in his own bed??

So my little step brother is almost 9. He sleeps with my dad and step mom. And has maybe only slept in his own bed a handful of times in his whole life. Also, every night he falls asleep on the couch and when he does, he is CARRIED UPSTAIRS TO BED. EVERY NIGHT. And when we go somewhere and he falls asleep in the car, he is carried in to wherever we're going. Like he isnt little by any means, I'm 20 an 5'3 and he's catching up quick. I feel bad because it's embarrassing to me. What are your thoughts? I know everyone parents differently and I would never say anything to my step mom about it, but it just seems...unusual.