"Can this be fixed or toss it"

In the dozens of pairs of lower control arms that i have rebuilt, i never have seen a crack in that area.
So if you don't weld, then your going to have to pay a welder in your city, the going labor rate to get it done.
Also, surgically removing a sway bar mount tab from the cracked one, isn't the easiest thing to do, either.
I use band saws, hand held grinders, Dremels, bench grinders, in doing that.
Time consuming.
Then your going to have to find a lower control arm without a sway bar tab on it, then pay the welder to also weld on the tab.
Or try and find a single LCA with the factory tab already on one.
Right now, i'd tell ya, find out what a welder would say.