My 1 year old is really interested in her older brother (4.5), and she is entertained & fascinated by him no matter what he talks & does. She can sit & play on her own (eg look at the toys he plays or grabs the toys he plays)next to him for an hour (without me present

) & he plays on his own. She often crawls to him wherever he is, but he rarely involves her at any play. Most of the time, he grabs back the toy what she holds at hand. For this 3+ years gap, what can they do together at home that is also interesting to my son?