How can I help our established Queen palms after the freeze?

Just trim the dead leaves and watch carefully over the next few months. Here are some great links for you!

http://homeguides.sfgate.com/prune-queen-palm-trees-after-freezing-57000.html

https://www.gardenguides.com/129476-frost-damage-queen-palm-trees.html

http://www.envisionlandscapes.net/blog/2011/03/21/Freeze-Damaged-Palm-Trees.aspx

It is always best to wait on pruning or anything else when trees are harmed from frost.Pruning will add to further stress.Wait until the have recovered enough before anything else gets done

I have a friend in Florida who has a few Queen Palm trees. She tells me that they are fairly intolerant of cold weather or temperatures that fall below 25 degrees C. Hopefully you do not have a situation where the trunk comes out of the ground easily. She did not have much luck there. She claims that before winter, she adds extra mulch around the trunk base, and also adds small miniature lights to use year round, to help with some additional warmth. Hopefully the damage you have experiences is recoverable and there is a positive outcome.

I would just wait out the frost, and let the tree recover a bit on it's own. When it gets warmer out, you can prune off the damaged parts of your palms