Are we talking or is he playing me?

So I like this boy he’s my best friends brother and I have always told her I had a crush on him. One day after her graduation party he text me and said he always thought I was cute and would like to get to know me and I said okay. (I asked for her permission about it before I agreed and she told me to go for it) This happened a couple of weeks ago. At first he was really good at texting me back and he would always text me hey I’m going to be busy today sorry if I take long to answer and i thought it was cute. Now it’s completely different he swears he likes me back but he never texts me. He sends me a text like 3 times a day and that’s it. I never get to see him either. I understand he’s busy because he has practice in the mornings and afternoons but he always has time to post on Instagram or Snapchat. I was so sad about it so I text his sister cause she’s my best friend about it. She told me i should talk to him and I said no not right now. Then she said you have to text him and i said please just let me be sad for a little bit. She got all mad and hasn’t text me at all today either. After I cooled down I confronted him about it last night and he said he was sorry for causing so much confusion and that he wanted to be with me but today it was the same thing again. He even deleted a comment I put on his picture when I called him my boo. He only deleted my comment though everyone else’s was there. I don’t know what to do. I feel like I lost my best friend and my crush at the same time. Do you think she told him something? Why is she so mad at me? Should I ghost him? Should I try to talk to him?