Generally speaking, yes. The purpose of the Reply brief is to respond to points made in the Respondant/appellee's brief. Any case law that the Appellant chooses to use to support the "replying" arguments is legitimate.
The possible exception could involve what we call "sandbagging" - where arguments or case law supporting the Appellant's main points are held out of the opening brief and presented for the first time in the reply brief, but that can be a very fine line to discern in real life.
If you Google search it you should be able to spot who is the Administrator (often a speciality firm such as Garden City Group) then call or send them an email and you should get your answer.
Please accept sympathies and best wishes for your daughter's recovery.
A class action is rarely the proper procedure unless dozens or hundreds or thousands of people are harmed, and even then it is rarely the best approach for someone who suffered physical injuries and damages.
It sounds as if the seriousness of the harm to your daughter would fully justify an individual action if the facts are borne out after investigation by a top-flight litigation / personal injury attorney.
It is a legal matter, and from the facts you've given us it sounds like the person who hit you is responsible for everything. Your paperwork from the investigating officer should tell you if the other driver had insurance coverage, which the next important question. If not, the next issue is whether you have uninsured/underinsured motorist coverage.
You should immediately consult a highly rated local personal injury attorney.
Even more important, scoring by wins and losses is a deceptively easy but inaccurate approach even when you can get to the data. Some of the best lawyers lose hard cases, even with the best possible lawyering, and some crappy lawyers win easy cases even though they may arguably be almost brain dead.
The Martindale rating combined with actual recommendations should be the best approach, combined with your reaction when you meet with someone to discuss your case.