So my sister in law and her two girls are staying with us til she moves into her new apartment next week and it's a huge change for my two year old son. He has issues with sharing just about everything. He has an older brother and sister, but he is not used to having a baby around his age that he has to get along with full time and have to share his "things" with. I am having to constantly tell him to share, and be nice. I am going crazy. I don't know what to do. He's never acted this way before. When I watch her during the day with my son, he freaks out if I have to hold her or anything. He's always screaming, "that's my mommy." I keep telling him, yes I am your mommy, but I am her aunt and she needs attention too. He also hates sharing his toys, but has no problem taking hers. He will hit her, or push her down. It just upsets me to see him act this way. I don't want him to be like this. Especially when he starts pre-k. If anyone has any suggestions please feel free to let me know. Thanks so much!!