crumbling brick wall
 

the unfinished basement wall brick is turning to dust. Need way to fix this problem. Can just use thin set for this pupose?

No, sorry.. Thinset will only mask the underlying problem temporarily. It will pop off and you will have an even larger mess to deal with.
You have one of those situations where a qualified contractor would be a necessity. And an engineer would be even better. Also, I'm sure someone will remind us that a building inspector should be involved. MA has strict code enforcement and the repair you're going to need will be structural.

of course you can,,, square eye's just giving you the right advice,,, its your house so have at it :rolleyes: if we were you, we'd tie a rope around ourselves so it'll be easier for survivors/1st responders to pull your body out of the debris.

in other words, this isn't a quick/inexpensive/diy-er fix.