yep, if you can cut and weld some steel, you could get away with just reinforcing that mount a bit so it doesn't bend sideways.

something like this...

 

woah!! yea, don't drive it off-road till you get some of that sorted out.

as you can probably tell, several directions you can go. just depends on what's your intended use of the jeep. lots of off-road or more daily duty?

Quick list of your options:
shorts arms - similar to your upper control arms. put short arms back on the bottom (may need to weld a bracket to frame side)
radius/ Y arms - short arm from lower (long) arm to upper axle side mount.
long arm upper link to match the lowers.

 

it's not gonna explode or fall apart on you. it may just bend a little. it's probably been like that for a while and wheeled just fine.

but in your best interest, i would add some plating at the very least.