My dd was 27-months-old when her twin sisters were born. It was a bit easier for me because we bought her twin baby dolls with a stroller that she could take care of also. Is your son into baby dolls? Maybe that would be an option for him. If he likes books then the Twins Magazine website (www.twinsmagazine.com
) has great books written for little ones who are having twin siblings. You could also find him a cute shirt like the one my dd has. Her's says "I'm a TERRIFIC big sister to twins!!"