Sun City Center area restaurants
Short answer? There aren't any. Everything in SCC is absolutely keyed to the retired crowd -- which might be exactly what your relatives enjoy.
Lots of casual restaurants around, a few of which are non-chain, but for white-tablecloth stuff you'll have to go to Sarasota or Tampa.
fine dining and sun city center are not typically mentioned in the same sentence. Several acceptable Mom and Pop Italian places. You need to drive over to Lythia or maybe west to Bradenton to find something good. Topping for you. You might try Yelp. I don't consider Yelp to have the quality of recs that the Hound does, but they do get many more hits. LMF