I wasn't able to bring my hibiscus plant in when it froze this winter, and the branches are now brittle. Is it totally dead, or can I bring it back to life?

I don't know if this is any help, but I live in Canada and we have a hibiscus that stays outside all year. Every spring after the snow melts the stalks are all brittle and dry so we snip them off. The plant then send up new shoots. Your hibiscus may be a different variety then mine, but from my personal experience, they are pretty tough.
It should be ok.

We have a large hibuscus here and it gets about 4.5 feet tall. Like the previous post says, ours does the same thing. The large stalks get brown and brittle and I just cut them at the ground in the spring. The plant sends new stalks up and usually gets even bigger each year. I have to brace it with stakes it is so tall now!
Is yours in a pot? It may not be OK if it is.

I think it may depend on whether you are referring to the tropical type of hibiscus or the perennial type more often referred to as rose mallow. The perennial type will die back to the ground each winter leaving just sticks and will send up new shoots in spring, sometimes late spring depending on warmth. The tropical kind usually will not survive below 32 degrees F, but might overwinter during a mild winter. The stems would probably be dead and it would send up new growth from the ground. If you don't know which one you have, just wait to see what happens in the coming weeks...and hope it comes back! :-)

Thank goodness for you Alanhart!!! This is true, there is two types of hibiscus..... One looks like a tree of dead sticks or twigs the other looks like dead bamboo canes, dried up and hollow...Look to see the tree one takes a long time to come back to life so to speak....Don't cut it til you know for sure!!!!!!!!!