First of all, it's Belial. Secondly, and I feel this way about every 40k player, lists should be made to be able to handle any army. Just sayin.
and i'm just saying that you could be more helpful than this.
well typically to kill termies can be hard to do for Eldar.
if he's taking LR's than the main thing is to take BL's: they treat AV 14 as AV 12, and due to low AP and high Strength, will cause termies to roll a 5++ save instead of their 2+.
Banshees also make a joke of termies as they have a high I, and they all have PW, but you MUST take a Seer with Doom/Fortune/Stones.
you'll simply have a hard time wounding TEQ's otherwise.
Fire Dragons are also a good option as they're fusion guns will melt most armor period. so a unit of them in a Falcon would be good against a command squad or anything that could threaten your tanks (say a TH/SS unit).
the best way to get several BL's is to take 5 man DA units in Serpents with TLBL. 4 Serpents with 20 DA (DA have no upgrades with this set up) is less than 900 pts. (check your codex).
in a 2K game that is perfect to take to Banshee Squads with Seers. fill out the rest of the army with Prisms or Falcons.
and yeah a list roughly along these lines should be able to take on most kinds of armies; it'll struggle against hordes a bit.
good hunting.