Yikes... What a story. I'm new to TX, but not new to carrying.
I did not see this in the OP, but once he "disarmed" you, did he clear and rendered your weapon safe, prior to handing it off to a 3rd (unknown to him) party? I presume (not mentioned in the OP) he did not check to determine your wife's LTC status, outstanding warrants or her past criminal history prior to arming her

? Based on your apprehension of him delivering an unholstered weapon to her, I'd tend to think he did not.
I would want to report to his department, if for no other reason then he could use some serious retraining (IMO). 1 is on the law (below) itself (as has been noted), and 2 is just disregard for his own safety.
1) Leaving the methods he took aside..... If he is moonlighting as a security guard in another county other then his primary jurisdiction, Is he really acting in the "lawful discharge of the officer’s official duties". Also, was it "reasonable" for him to think that it was necessary to disarm you for everyone protection under those circumstances? The law seems pretty specific to me. Look at it this way, if some plain clothed person approaches you, flashes some tin and says "he's the law" and want's to disarm you for his/our own safety (assuming you are legally carrying)? Would you just comply? That's hyperbole of course, but still... the point remains?
2) This is just a basic safety thing to me. Why the heck would he just hand YOUR weapon to an unknown (I presume he does not know your wife) 3rd person. For all he knows, he just armed a convicted felon? Or some other person that should not, or could not be in possession of a weapon? If he did not hand it to you directly, then place it on the passenger seat where YOU can take possession of it. That's what the statue directs (see below). Seems pretty reckless to introduce a third party (that he doesn't know) into the situation that involves a potential deadly weapon??? Sounds like a recipe for disaster to me (for him). It's also a violation for him to do so.
Did he ever even check your LTC status?
GC §411.207. AUTHORITY OF PEACE OFFICER TO DISARM.
(a) A peace officer who is acting in the lawful discharge of the officer’s official duties may disarm a license holder at any time the officer reasonably believes it is necessary for the protection of the license holder, officer, or another individual. The peace
officer shall return the handgun to the license holder before discharging the license holder from the scene if the officer determines that the license holder is not a threat to the officer, license holder, or another individual and if the license holder has not violated any provision of this subchapter or committed any other violation that results in the arrest of the license holder.
(b) A peace officer who is acting in the lawful discharge of the officer’s official duties may temporarily disarm a license holder when a license holder enters a non-public, secure portion of a law enforcement facility, {snip.....}