Have you ever heard of anyone being told they couldn't buy a handgun because they expressed their opinion?

Now, this story concerns my brother-in-law (honestly, this isn't about me.) He is a disabled veteran, had been diagnosed with PTSD, has some issues resulting from chemicals he was exposed to in Desert Storm, and also has a physical disability from a helicopter crash he was in while serving in Iraq. (He was in the Marine Corps.)

Most of the time he seems fairly normal, conversationally, but sometimes he will get very excited, talking fast and waving his hands, and then he loses his train of thought and frequently changes subjects while he is talking. He does sound like a nut case when he does that.

He called me last night, saying that he had been in Academy Sports, trying to buy a handgun...while he was talking to the counter salesman, they got to talking about the conditions currently, and my BIL said that while he was expressing his opinion, a supervisor/manager walked up and told him he couldn't buy a gun there and asked him to leave. He said that if the supervisor or manager had come up a little earlier, he would have heard the counter salesman expressing the same disgust with "things" as he was. (For the record, I've never heard him threaten anyone, or make any statements that would lead me to assume he is dangerous...he gets excited and forgetful, but I do not think he is or has ever sounded violent. He has also bought handguns before, at a gun shop, and passed the background check, evidently.)

He said he went to another Academy Sports store, and they told him he was in their system as unable to buy a handgun from them for 30 days...it wasn't a background check issue, because one had not been done yet (apparently he filled out the 4473, but they hadn't processed it yet.) He said he was told it was "store policy" and each store had the discretion to refuse to sell, and other stores had the discretion to abide by that in their own store. He said they did sell him a shotgun at the second store, though.

Now, this is all by his account...it sounds very bizarre to me. Like I said, I've never known him to make any comments that would make me believe he has any issues with violence, paranoia, etc. I thought about calling Academy Sports and seeing if I could verify that, but I don't know if they'd talk to me about it...I have no authority, power of attorney, or guardianship over him, etc.

Has anyone heard of anything like this?