Charges Over Altercation At Work

I live in Florida and my father who is 62yrs old had an altercation at work with a fellow employee. He has two charges against him Battery and Assault with a Deadly Weapon. The Battery charge is a no brainer he hit the guy but the assault with the deadly weapon charge is where I need help. My father has carried a pocket knife on him since he was 12years old with a blade no longer than 2in or less. When they arreseted him there was not a knife on his person. He has no previous record and they are trying to put him in jail for 90days. I am curious to know if there is something in the law books that say that a pocket knife is not considered a deadly weapon. Any help would be appreciated

He threatened the person with a knife?

No proof of him doing so his word against my fathers he stated that my father pulled a knife out of his pocket. The offical charge is assault with a deadly weapon without the intention to kill Fl statue 784.021 (1A) but there was no knife found on my father at the time of his arrest. Its a he said he said kinda thing. I just want to know if there are different definitions of the weapon in the deadly weapon part of the charge (ex. certain lengths of blades etc.)

A small knife can be a deadly weapon.

We went to court this morning the deadly weapon charge was dropped by the state insufficent evidence was the call. Thanks for all the help :D