I'm currently on vacation at a resort and am pretty into a girl, she has been flirting with me with all of the sqeezes my hand while holding, playing with hair, laughing at every i say etc, but my problem is her brother

she is with her parents here so as a result her younger brothers are with her, pretty sure the oldest one is 18, while we're closer to 22, he is hovering like a mother fucker and i honestly just feel weird as fuck trying to make a move / knowing what to say to succeed in this situation.

yo?