Hello, first of all, I mean I'm Spanish, and use Google Translate to write the theme, so I apologize for spelling errors and inconsistencies.
I have the following problem, when entering the casino the inventory of my classmates disappeared, I lose all its contents. I was forced by commands to retrieve the weapons he had, because I thought that by entering them in the casino, as I removed my arms to them too, and that due to a bug they may not recover. But not, I have only to enter a casino, for example Gomorrah, and the inventory of my companions disappear. Veronica I have as companions and Rex, with many valuables, and other unique weapons, and I've lost everything. Please ask for a solution, once again, apologies for the vocabulary. Thanks and greetings!

Ehm, when u leave the casino the weapons should be returned (after the loading screen) to both u and ur companions. If this doesn't happen it must be a bug/glitch and there is not much u can do other than reload the game. But perhaps I have misunderstood ur post, Google Translate made a bit of a mess here

yeah, companions losing inventory leaving a casino is a known bug.....