Well, I hope the cuffs were taken off shortly after they cleared the owner of any wrong doing.
I suspect he did not even spend the night in jail, although its possible. Even the most antigun prosecutors who oppose your right to protect yourself hate to put something like this before a jury because they know damned well the chances of acquittal are extremely good, if it even makes it passed a judge, and they care more about their record than their principles. Some times they get a real bug up their ass and try to argue 'vigilantism' or some other heap of steaming dung, as they tried (unsuccessfully) when prosecuting Bernie Geotz in New York City.
Unfortunately, when ever any person is put on trial, there is a risk that you'll get an unusually stupid representation of the public as your jury and be convicted. Look what happened to that elderly man in England who shot two robbers in HIS OWN HOME. Convicted of murder (later reduced on appeal).
NEVER give a statement to the police without your attorney - EVAR. You give them your vital info; name, age, address, etc. If they ask what happened, state "I was defending myself, I thought he was going to kill me." Say that more than once. Several times, preferrably.
If they try to get you to make more in depth statements, politely (always be polite!) refuse to answer any questions without your lawyer present. Request a lawyer the first moment they try to interrogate you beyond your name, rank, serial number, etc.
As much as I respect the difficult, dangerous, and thankless job we as a society ask of our law enforcement officers, I do not trust law enforcement one bit. There are far too many examples of innocent people getting ramrodded and shafted because they held the misconception that 'innocent people cooperate' while 'guilty people lawyer-up'.
In their zeal to cooperate because they believe they have nothing to hide or fear, incompetent or unscrupulous investigators - and there are many - are manipulating them into giving statements that can be construed as damning and used against them in court.