If you are selling the property as a listing agent then you are representing the seller and thus would fall under the normal parameters of a property listing and commission splitting. 

The option to quit a job with a middling base salary, for example, and take a more commission based sales job with a lower base salary might become an opportunity instead of a risk.

Call his broker ASAP and then file a complaint with the state Real Estate Commission.  

It's worth just about the same as I paid for it, so after fees, commissions, etc, I'll basically walk away with $20k if I sell it.I assume if they do the foreclosure, they'll either simply place a lien (since the bank is first priority) or take the property subject to the mortgage (and I guess pay the mortgage?).

There may be a commission involved, but at least you'll have the right audience of buyers. 

and "What about my commission?"  

Usually the agent on vacation has a colleague cover their business while they are gone and share some commission with them on the deal.If the agent is a long time professional the business doesn't just stop while on vacation you have others cover while gone etc. 

How will the commission and all expenses related to the selling affect the gain?

I am also a broker in Vegas but do not want commission. 

They honestly aren't the best to work for, since most of the time they aren't loyal, they undercut your commission, and most are unrealistic.