trying to figure out deeds filed

[mrss]

What is the name of your state? Colorado

I am trying to figure out some information I found while doing internet research from the registry of deeds. My parents bought a house in Colorado in 1982. It was my understanding that the house went into foreclosure years ago, but I didn't know exactly when or the details. I didn't care too much about it, but my half-brother has been making an issue out of it for years. He believed that the house was sold, and that somehow he's "owed something" even though he was a minor child at the time. I am afraid that this issue could come up again when certain relatives pass away, so I researched the records to find out what happened. I am trying to figure out what these deeds mean.
Initially a "warranty deed joint tenancy" was filed with my parents as the grantees and the couple they bought the house frome (I'll call them Mr and Mrs X) as the grantors. The same day a "deed of trust" was filed with my parents as the grantors and Mr and Mrs X as the grantees. About five months later, a "notice of election and demand for sale" was filed, listing both my parents and Mr and Mrs X under both the grantor and grantee columns. This was filed a few days before we suddenly moved from the house. As a child, I was told that the house was being rented "by the bank" somehow while we lived elsewhere, but obviously that was not the case. About two months later, a "public trustee's certificate of purchase" was filed listing my parents as the grantors and Mr and Mrs X as the grantees. Finally about two and one half months later, a "public trustee's deed" was filed listing my parents and the county of Boulder as the grantors and Mr and Mrs X as the grantees.
My interpretation is that instead of using a bank, my parents had a private mortgage with Mr and Mrs X. When my parents couldn't pay, the mortgage was foreclosed upon and Mr and Mrs X took the house back. Does this sounds correct? Also, is it not completely ridiculous of my half-brother to believe that he is owed something from this fiasco? I am guessing that we were abandoned the property instead of defaulting on the mortgage and that there was no profit to us involved. Any help with this would be much appreciated. Thanks!