Family trip to houston – suggestions on where to go?

I'm going to Houston in November with a few adults who's in their 60s. I plan to do some date nights but also take everyone out to sightsee on a few days. Anyone have suggestions on:

1. Best food places, hole in the wall, really good restaurants?

2. Restaurants that are good but also have selections for people with strict dietary restrictions?

3. Sightseeing for older people? free things to do?

4. Any casinos or fun night out activities?

thanks 🙂