What offenses do you see with these facts:

26 year old security guard has 19-20 year olds at his and his mother�s house. His mother is 52 years old. Everyone is drinking and playing cards. Mom goes to bed as do two other 19-20 year olds. The security guard gets out his guns and shows them to the remaining crew. After a few more rounds the security guard says he passes out on the table and the two remaining males decide to play Russian roulette. The drunk (we think drunk, the toxicology isn't back yet) 19 year puts a gun to his forehead and he's dead. The awake witnesses say the dead 19 year old went in the security guards room and got the bullet. Definitely providing alcohol to a minor but what else, if anything, do we have on security guard?

Assuming the defendant was not presumed to be traveling... Really - criminally negligent homicide (defendant engaged in activity that could have foreseeably resulted in death). Or deadly conduct. Those are the only two that come to mind this late in the day that don't appear to present you with any intent issues.

I do not think it is a criminal offense. How could you ever prove that the security guard either knew or should have known that someone would retrieve a bullet and then engage in Russian roulette and kill themselves?

I'd go criminally negligent homocide. He should not have served minors beer. As part of his training to be a security guard (assuming there was some) he has got to have taken an alcohol awareness class that emphasized that guns and alcohol can be a lethal combination. Find out where he went to school, if so, and subpoena records to get someone to testify to that fact. Further, the minors knew where the ammo was kept (assuming you believe that story), so it certainly was a gross deviation of the standard of care to supply a deadly weapon to a minor who had been consuming alcohol (especially because he was unable to supervise), and allege your deadly weapon for third degree.

Lastly, charge the friend that thought Russian Roulette was a good game to play drunk, with ammunition in the gun, under law of the parties. He encouraged both a fortunate and unfortunate result.

Just a thought

Criminally negligent homicide probably will be the order of the day. Besides that, donning my Carnack the Magnificent headgear, I foresee fairly significant civil litigation against the security guard's employer on a negligent entrustment theory. Thus, I would be cautiously aware of the prospect of your office being used as a putative source for juicy discovery in that all-but-certain civil action.

From the Acme Security Officer Academy training manual:

Chapter 1
Point your flashlight toward the darkness. Do not use it in daylight, unless you need it to prop open the door to the kitchen (after the cooks leave). Make sure you remove any kitchen door props before your shift ends or before dark. Don't eat raw meat you find in the coolers; try to satisfy yourself with cookies and pastries left out by the cooks.

Chapter 2
Put your car in park before you fall asleep.

Chapter 3
Cover up your prison gang tattoos while on duty.

Congratulations, you have successfully completed security officer (we're not guards!) training. You may refer to this manual periodically as a refresher or to prepare for promotional examinations.

I'll bet they don't have their trainings in Corpus !

They train in Pasadena, Texas.

But every other year, they go to Ree-uh-doso and play the ponies. With their flashlights. And they drive through Amarillo, despite the fact that they're coming from Southeast Texas, so they should drive straight through the beaches in Midland to get there.

Returning to the original subject matter, if it still exists, has the private investigators board been notified and are they planning to do any investigation? Perhaps there have been prior complaints that might shore up an air of recklessness with respect to your potential defendant.

So it is reasonable to assume that your house guests will commit suicide?

Should the security guard also have hidden all of his kitchen knives and anything the teens might use to hang themselves?

Consider charging the surviving minor with attempted murder... of himself.