21 and flirting with 14 year old?! help?

Well my sister bf is criplled and I help him around a lot in a wheel chair and can't walk. And he stays the night with me and my sisall the time. he's 21 and I'm 14. Late at night we have talks and he said last night he wishes iwas my sister. And he stares at me in tensely and likes sharing food or drinks with me. Sometimes when we share a popsicle he askes me to feed him.and he buys me stuff all time. Is flirting or what? What do I do?!?