How to fix crack in slab foundation wall has 90 degree turn to horizontal below the surface?

First, is this 90 degree switch from the vertical wall to horizontal bottom a normal feature of slab foundations? This is a 1953 ranch in northern Ohio. Red arrow in photo indicates the turn to horizontal.

Second, until I dug down to find the crack extends into the horizontal area of foundation, I was going to use Loctite PL concrete polyurethane sealant. Is that still a reasonable solution, or is it time to call in the pros? The gap is easily 1/2" or more in some portions of the crack line.