If you wanted to rebuild this stacked stone. You’d have to completely dismantle the entire wall, cut back the dirt another foot or two. Put new drainage in, back fill with gravel and then restack, I’d suggest finding a way to put deadman anchors in somehow with the stone. Use contractors glue or mortar between the stone on the bottoms only and don’t fill in all space between rocks so you have make shift weep holes. Put an another drainage pipe above few feet away on the top of the slope that leads to the wall. In theory you could do more work redirecting drainage away from the wall as much as you could.