Relevant law:
776.032 Immunity from criminal prosecution and civil action for justifiable use of force.—(1) A person who uses force as permitted in s. 776.012, s. 776.013, or s. 776.031 is justified in using such force and is immune from criminal prosecution and civil action for the use of such force…
I think that this is what will cover him from that civil suit. It will probably make it to a hearing, but should be a slam dunk considering that he was found to have been covered under the SYG law.