So your boys are about 5 years apart which is easy for me to relate to since my bother and i are 6 years apart. i had the same problem as your little one. My mom tried everything to get me to ease up about not being around my brother but nothing really worked. It's because since he was so much older than me and stood up for me all the time around the other kids it became a sense of protection and safety for him to be around. He was my security blanket, my best friend, my partner in crime, he was my older brother. But a time comes when hanging out with your little sister or in your case brother isn't really "cool" anymore. Although my brother would never let me see that he just tried to back off bit by bit. Still never worked. So my nana stepped in. She found a figureskating class at the same rink my brother played hockey at. Better yet at the same time but the class was for only with kids my age. Thats how my parents got around how my brother couldn't be there. Which made me feel special. So we were still doing things together but not "together". The separation issues stopped, i fell in love with something newand a few months down the road i didn't even realize my brother was no longer hopping out of the car with me.There are alot of other places like that depending on where you live. Some sports leagues have different ages practice at the same time just on different fields or on other sides of the gym. Some gymnastic gyms are like that and if you're lucky even a karate studio might have multipule classes at once as well. Hope that helps.