Setting Boundaries with a Family Friend

I’m having a bit of trouble with a slightly more than friend. We’ve texted back and forth discussing how we felt about each other and decided to wait before dating but near the end they send unwanted suggestive stuff to me not like anything illegal but I still didn’t want it. I’m concerned that they will want a sexual and intimate relationship which I really don’t want because I’m abstinent and don’t view intercourse as a recreational activity. I’m honestly scared that it will end up like my first relationship where they tried to rush it to making me hold hands hug etc. The worst part is they’re a family friend so I can’t really tell anyone I feel trapped and I can’t text or call them or even visit them because they are visiting their parents and won’t have their phone with them out of respect. I want to set up these boundaries for when we finally date if we do but I’m also scared they will turn up unannounced at my home because they want to visit and can’t text ahead of time.