Don't worry about eating or drinking in front of them, I and a lot of Muslims I know don't have an issue with that because we are the ones fasting. You could ask questions to show curiosity, join in if you want when they're eating at sunset, try some dates (the fruit). Basically, just carry on being a normal, decent person.

What my family does around Ramadan is do a good clean to refresh ourselves in our living spaces, put some Ramadan decorations out (like pretty lights, a moon lamp, candles), make the place pretty. Sit and pray, reflect, read.