I don't know about Texas, but here in North Carolina, if you rear end someone at night who's tailights/break lights are not functioning properly, or not working at all, it would be considered contributory negligence. Both driver's would be found at fault, and your insurance company wouldn't have legally owed that douche a dime under NC law. Under that law, if a driver is found to be 1% at fault, he/she cannot recover for damages or bodily injury because he/she would have "contributed" to the accident. He should have made sure his truck was functioning properly prior to driving it at night, and you shouldn't have been going that fast. Just glad you're alright.
1998 Tacoma reg cab 4x4 2.7
OME 881's, OME shocks, OME Dakar leafs
32x11.5 BFG AT's