The age of the person who committed the offense is very significant. It does not matter that they are all adults now. While there may not be a statute of limitations for prosecution of such an offense, conducting an investigation and determining whether or not the 12 year old at the time of the incident was legally capable of committing a criminal act would be near impossible.
The law is extremely specific about the types of acts done and the intent of the person committing the acts. What one person believes is a serious sexual offense may only be a minor offense, and what another thinks is no big deal could be a felony.
I highly doubt anyone could ever get reliable testimony and evidence from the victims 14 years later, considering they were only six at the time.
Basically, what I am saying is that the two victims should not hope for any sort of closure through the legal system. As you describe it above, it just won't happen. Counseling is probably the best option.