My 5 year old is being mean to me and to family members and I’m not sure how to fix it.

My son’s mom and I are not together anymore, but we have joint custody. I’ve been involved in his life since the day he was born, I have him every week, etc. He’s always been comfortable with me.Over the last couple of months, my son’s behavior has really deteriorated in some ways. He’s always been a super sweet kid who loves everyone. But lately he’s been disrespectful and downright mean at times. First, I call him on the phone every day we aren’t together as part of our custody agreement. Now, I recognize that talking to daddy on the phone probably isn’t the most exciting part of his day, but we’ve always done okay. Recently, though, he’s taken to shouting into the phone “Hi, I don’t want to talk, bye!” repeatedly, and then hanging up after about 30 seconds. I’ve been trying for weeks and I can’t get him to say anything else. His mom, for her part, refuses to intervene, and my son doesn’t act this way when he talks to her on the phone. So I don’t know what else to do.Second problem is my son’s behavior toward me and family members. We’ve always been close with my sister, her husband, and their daughter (2 years old). My son has stayed with them, we’ve seen them hundreds of times. They are very good to my son and always have been. Lately, though, any time we try to see them, my son throws a complete fit. “I don’t wanna see [sister]. I don’t like her.” “[baby cousin] is mean to me and scares me. I don’t wanna see her.” Etc. Cue complete meltdown. Eventually I end up dragging him kicking and screaming to whatever we’re doing, and after a few minutes he calms down and acts normally. He also has taken to telling me “I don’t love you” when he is mad at me or doesn’t like something I’m telling him to do (petty stuff usually, like putting on his shoes).Now, I’m sure he has some stress associated with having two families and two lives he lives. He also recently started kindergarten and immediately got moved to first grade, so that may be a factor as well. I’m just at a loss for how to help him be happy and behave better and I’m getting no help from the other parent.Any advice would be appreciated. via /r/Parenting http://ift.tt/2xhtMda