Without changing your list...Theres not a lot you can do to fliers.
Your heldrake can do a bit - are you allowed to swap the baleflamer out for the hades?
Short of measuring exactly where they can get to with 24" movement and making sure you're 30" away. That way they can't vector strike you and the turn after, you power underneath them with rhinos - in order to get you when you're behind them, they have to land. Doesn't work very well though.
Or annihilate all his troops - if he's spent 640pts on fmc's, how much demon could he get for 360pts?
Exactly. try to win the game by objectives, focus every shot you have into the 2 monsters, use hades autocannon on drake, remove the sorc on his own and add another melta and body on the marine squad. With remaining points, buy 2 icons of vengeance for not running away.
Otherwise, completely change list, if the local lists are cheesetastic loads of sh*t like the daemon list you speak about