Bismillah I think the sister already said they are not practicing shia. So my advise would be the same as the other but invite them to your place and give them subtle dawah. Do not get into relegious conversation with them but focus on the 5 fundementle. As for food tell them where you get your meat and food stuff from casually and enquire where they get their stuff. If they are ignorant in thier shism, they will adopt sunni islam any way by the virtue of their education. Do not go down the route, we sunni, you shia. Most ignorant shia could not care less. No matter what always be good neigbour. This is the rights of neighbour. Allahualam