What happened on that convention? Read the article but doesn't seem like they mentioned anything about it unless I missed it.

Larry Nemecek has a bit more info on his own website.

There's also a bit of info in this Houston Press article from 2014:

In 1982 there was supposed to be a con to end all cons here in Houston. And there was, but not in a good way. It was billed as the Ultimate Fantasy, a product paired with the respected name of Houstoncon, which had been providing a quality and successful con experience in the city since 1967.

Thereafter it would be known as the Con of Wrath, or the Ultimate Fiasco, and its failure is the stuff of geek song and legend.

[…]

Ultimate Fantasy was ambitious even by today’s standards. It was to be a huge stage show hosted in the Summit and featuring a rotating stage and a laser light display. The guests would be most of the stars of Star Trek: The Wrath of Khan, who would re-enact parts of the film. Nothing like it had ever been done before, and Wilhite was convinced he could pull it off.

So convinced, actually, that he got several investors to mortgage their houses. Billboards went up all over the city. Ads appeared in TV Guide and Starlog. Wilhite believed that Ultimate Fantasy and the associated Houstoncon at the Shamrock Hotel would draw 10,000 people, including Trekkies, from as far away as Japan and Europe.

Organizers needed 5,000 people just to break even. Two months before the event, barely 400 presale tickets had been sold.

[…]

When the stars of the convention appeared, they found out that their hotel rooms hadn’t been paid for. They were forced to pay out of their own pockets.

As the con progressed, it became apparent that the thousands of attendees needed would not appear. Vendors and venue realized that they were not going to be paid. Shamrock management contacted all the dealers in the hotel and told them that unless the remaining balance was collected by that evening, they would all be thrown out. They passed the hat to keep the doors open and hoped to sell enough to recoup their losses.

And Jerry Wilhite had disappeared. No one could find him. Or any of the money that was supposed to materialize. With him he took Houston’s reputation as a place for comics and science fiction pop-culture acceptance and celebration. Word went out from guests and dealers alike to avoid the city. The people in Houston didn’t know what they were doing.

[Edited to add source link]

Oh! Oh! It gets better!

[After failing at running comic shops as well,] Wilhite started attending Lamb of God Lutheran Church in Humble in 1989 and wrote a Christian memoir looking back over his involvement in comics and gaming. In it, he warns readers about the dangers of occult activities like playing Dungeons & Dragons or watching horror movies.

Apparently all his failures were not due to his own shortcomings, but signs from god to stay away from all of that occult scifi stuff or whatever.