The man has a point.
If the axle is on the truck its even harder, cos the welds are all upside down and in nooks and crannies.
Best bet is fabricate a complete new bracket in the workshop, then cut the one off the axle and weld the new one into place.
Better done with the axle out of the car so you can tilt/rotate it to get the best angle for welding etc.
If you are new to Mig, Id get someone with experience to do it, It is a very important item, and a botched repair could lead to injury/death (maybe someone elses)
If you can weld, then go for it, but Id still pull the axle, Itll be a neater job.