I have included the Florida statue of leaving the scene of a motor vehicle crash below.
The penalty if there were no injuries can be up to 60 days in prison. This does not mean that will be the sentence, this is the maximum sentence that could be imposed if convicted.
Under the Florida statues I have attached the law applies to the person driving the car at the time of the accident and not the owner. If there is a witness that can identify the car only that will not be good enough. They need to be able to identify the driver.
Unless the letter from the police has information showing you as the owner are responsible, it is up to them to determine probable cause before they charge someone. I think the key is can the witness identify the driver?
Based on the limited information I would suggest that you engage an attorney and attempt to negotiate a deal with the other car owner to pay for the damages without identifying your boyfriend.
I have 22 years experience, as a police officer and I believe if they had enough information to charge you they would not have sent you a letter but would have sent you a summons.
Finally you have two choices as I see it. First cooperate and give your boyfriends information over to the police and let him fight it in court or don't cooperate and wait for their next action
316.061 Crashes involving damage to vehicle or property.--
(1) The driver of any vehicle involved in a crash resulting only in damage to a vehicle or other property which is driven or attended by any person shall immediately stop such vehicle at the scene of such crash or as close thereto as possible, and shall forthwith return to, and in every event shall remain at, the scene of the crash until he or she has fulfilled the requirements of s. 316.062. A person who violates this subsection commits a misdemeanor of the second degree, punishable as provided in s. 775.082 or s. 775.083. Notwithstanding any other provision of this section, $5 shall be added to a fine imposed pursuant to this section, which $5 shall be deposited in the Emergency Medical Services Trust Fund.
316.062 Duty to give information and render aid.--
(1) The driver of any vehicle involved in a crash resulting in injury to or death of any person or damage to any vehicle or other property which is driven or attended by any person shall give his or her name, address, and the registration number of the vehicle he or she is driving, and shall upon request and if available exhibit his or her license or permit to drive, to any person injured in such crash or to the driver or occupant of or person attending any vehicle or other property damaged in the crash and shall give such information and, upon request, exhibit such license or permit to any police officer at the scene of the crash or who is investigating the crash and shall render to any person injured in the crash reasonable assistance, including the carrying, or the making of arrangements for the carrying, of such person to a physician, surgeon, or hospital for medical or surgical treatment if it is apparent that treatment is necessary, or if such carrying is requested by the injured person.
(2) In the event none of the persons specified are in condition to receive the information to which they otherwise would be entitled under subsection (1), and no police officer is present, the driver of any vehicle involved in such crash, after fulfilling all other requirements of s. 316.027 and subsection (1), insofar as possible on his or her part to be performed, shall forthwith report the crash to the nearest office of a duly authorized police authority and submit thereto the information specified in subsection (1).
(3) The statutory duty of a person to make a report or give information to a law enforcement officer making a written report relating to a crash shall not be construed as extending to information which would violate the privilege of such person against self-incrimination.
A violation of this section is a noncriminal traffic infraction, punishable as a nonmoving violation as provided in chapter 318.
For a misdemeanor of the second degree, by a definite term of imprisonment not exceeding 60 days.
If you have any further information please let me know.
Hope this helps,