pending arrival of baby #2? Too young to care or notice?

DS has never been a cuddler. He's definitely affectionate, but not a huge cuddle and sit/lay type. Lately he's been such a lovable, huggable, "lay with me umma" cuddler and I'm soaking up every minute!! (there are also days that are exhausting because only I can do things for him...)

He loves on my belly, says hi/kisses his baby bro, and feels kicks at least once a day. But, I'm not sure if he quite gets that a new babe will be coming to live with us in a few months!