Help with what to say??

My little sister is talking to my brother in law. She lives in a different state. She comes up a lot though. Well, first he was all the time he loved her and couldn’t be without her so she thought she was gonna try, she went back to Georgia and couldn’t do it so she broke it off. She took some time to herself. After a while, she realized that’s who she wanted. She could do. That she was miserable when they didn’t. So they got in contact again. She come up here, he said he was all in. He wanted her. He wanted to be with her. Well, than he stopped FaceTiming her. Stop replying to half her text. Would leave her on read. She finally just come down to it and just asked him if he wanted to be with her or not, instead of saying no, he said yes he wanted her. Well, than he started ignoring her again. Sending her maybe 2 text a day. Finally, he sent her snap that said i thought we needed some space, but now I want to try, so she put it all in, and he is doing it again.

(Not to mention, last time she was down here, it took her a week for him to come and hang with her, but once he did, he was always over.)

I tried to tell her to leave his ass on read when he feels like talkin. What would be the appropriate thing you think?