1996 Honda Civic 4 door. Usually have to turn the ignition twice to start the car. Went to dinner and when we got in the car to leave, the car wouldn't start. The car was trying to turn over but wouldn't. Thought it was the fuel pump. My brother checked it and it was fine. Fuel filter was fine. Timing belt fine. We can't figure out what might be wrong. Any advice would be greatly appreciated. Please help!!!

Go to youtube. Search "hotwire 1996 civic". Several videos.

They are successful in the videos. I've never had to try.

You can also go to deal with VIN and registration and get your keycode. They can provide a key or see a lock smith.

Follow the given link, maybe you get something useful.
https://www.reliable-store.com/products/honda-civic-service-repair-manual-1996-1998-download HONDA CIVIC SERVICE REPAIR MANUAL 1996 1998 DOWNLOAD

Even with the reprogrammed key's the engine would crank, it might not start but it would crank over so that leave's only one thing, your used ignition switch is bad.

Look under the dash all the way beside the drivers door. bolted to the wall is a relay about 2 inches by 3.5 inches wide and about 1.5 inches thick. Its called a MAIN relay. At o'reilly auto parts the number is R3046 by BWD. Its a simple plug in connection. I'd try that first. And trust me, ask for it by the part number, not the application. I worked there at one time.

Check fuel pressure with a gauge on the motor
Check volumn as well

See if the fuel pressure holds KO/EO

the electric switch at the end of the ignition barrell needs to be replaced

check for spark, if no spark suspect distributor, coil, igniter or complete distributor, crank sensor etc.......... and also open oil filler cap crank engine see if camshaft is turning (valve moving) is timing belt changed

Could be fuel pump ,fuel pump relay,or bad ground wire.

1. It's not the voltage regulator, that only controls the batter getting charged and at what rate.

2. It's probably not the ELD, if it was, you could go autozone (does this for free) or another friendly parts store and have them pull the OBD II diagnostic codes ... if the ELD is bad,  it would probably be throwing code(s).

3. It may likely be the ignition switch ( electrical contacts probably or maybe mechanical part)

Honda had some problems with ignition switches going bad prematurely in the 96-00 timeframe.  Go to the official Honda Owner Link website https://www.ahm-ownerlink.com/ and join there and plug in your VIN.  There was a recall for ignition switches,  they will let you know if yours is one.  It's not out of the question that they would still repair for free(that's why you got a Honda in the first place!).

yeah that could be one of the problem.