Rust repairable or not? JEEP GRAND CHEROKEE III (WH, WK)

I just noticed sevre rust damage under my jeep. Just beside the pinch weld. In the photos is the worst side but all other 3 similar areas are headed that way. Is this repairable with it being cut out replaced and welded or would it be structurally inappropriate?

 I bought the car for cheap and didn’t noticed this when looking over the car. Intact I’ve been under the motor several times replacing a few things and never caught my attention. I have no idea how this passed MOT in February with the previous owner. Can’t see this sort of rust developing this badly in the last 8 or so months especially in Northern Ireland. 

Looks like the previous owner was using this as a jack point and pancaking some of the pinch welds etc.