Should i be worried

My younger sister has this online boyfriend they never met in person and live in different countries all their mutual friends are online friends

He video called her today asking her repeatedly if he can unblock a girl he had an interest in one he knows my sister doesn't like her

But he kept telling her he not into this other girl he just wants to know if he could unblock her

My sister said he can do what he wants

Tbh im worried about her my sister is 19yrs old this month she an adult so i cant tell her what to do etc

It not my business just i feel like he up to something 😐😐