"has settled but because that brick foundation is under the area it cannot settle with the rest of the house."

Brick foundations settle like any foundation. For some reason, your house isn't "settling" evenly. If this happened over a lifetime, it is probably nothing. If the joint just opened recently, then it should be investigated immediately.

BTW - sawing out the foundation won't make it "settle". All you would be doing is destroying the foundation.

I don't think I've explained correctly. I guess you could say there are six foundation under the livingroom. Pretend the real supporting foundation is a big box. Set a small box into that box butted into the corner. The inner two sides of the small box are just there. The inspecter said the little box foundation would've been a set in porch but plans were changed and the room was extended across what would've been the little porch. The crack is directly above the edge of the small box. Looking into that crawlspace I also see a nice brick support column so the little box foundation is not needed to support the floor. Please ask if you don't understand. It's hard to explain.

I think you are explaining just fine, but I don't think you understand the possible consequences of what you are proposing. Whether you think this foundations is "real" or not, if it is keeping a portion of your house from sinking with the rest. If you try to destroy it, you do not know what will happen. Even if it just drops 1/4", what else drops 1/4" with it? Part of a wall, plumbing, air vent? I assume you don't want to trade a crack in the floor for a crack in the wall and ceiling.

A general housing inspector is not qualified to make a recommendation about this other than "hire a structural engineer."

Got it. Thanks

Even if the foundation in question was not designed as a supporting foundation but for a porch that wasn't built, over a century it could well have become a supporting foundation.