Your son needs a lawyer right away. Yes, the charges can still be filed. Your son, may have a defense, but I can't be sure without knowing more of the facts. I handle cases in Orlando and Kissimmee. Call me and set up a free consultation on Monday.
Your question asks what is the "statute of limitations" for those offenses. In Florida, those time limitations are controlled by Fla. Stat. 775.15 - I will try to post a link below to the statute which lays out the different time frames for crimes. Assault is a 2nd degree misd., for which there is a 1-year time limitation, and Battery is a 1st degree misd. and has a 2-year time limitation.
Whether you can 'press charges' in criminal court is a matter that is ultimately decided by the State Attorney's Office, but they are currently prosecuting your son so it is hard to say what they will decide.
I do recommend hiring an attorney as this matter could likely go to a jury trial - my practice focuses on So. Florida, but I highly recommend attorney Scott Harrison for any criminal matters in the Orlando area.
It would depend on what they could be charged with. The state has 179 days to file charges since they are felony charges. Just because the victim does not want to go forward does not mean the state won't still try. I would suggest your son hire an attorney to help with this.
For more information contact the Law Office of Corey Cohen at 407-246-0066 or visit our website at www.coreycohen.com