Help. oldest graft just got plank of wood dropped on it. what to do?

[SirLSD]

this is my oldest graft. it was on a tree sized PC in the ground a few years ago. then cut down a few years ago and the short branch potted. it lost over a third a few years ago but the rest recovered. it hasn't been looking great this spring with small patches of that dreaded orange rot showing on little scratches and cracks on its surface. I was hopping it would come good this summer then I was going to cut off a few big heads and try to get them to root. despite having aweful luck rooting pups off it previously. but after 10-15 years on its stock it might be due for coming off. 2 hours ago it had a plank of wood dropped on it which hit the centre of the original head and tore it down the centre. what should I do now?? let it heal? split it up into the biggest pups and try to get them to root? take some pups off to root and leave the main one to heal??

 

[SirLSD]

well I gave it a little sun this morning and the smashed out side has dried out on the surface ok so far. no squishiness or orange rot on that wound yet. I am worried that as the wound goes down to the centre growing core part (whatever that is called) that the orange rot that is on other surface spots of the plant, will infect it systemically from this central point out, and the whole thing will rot. I might take off one or two big heads tomorrow and see if they will callous without getting orange rot at the cuts. any advice? I was going to dust the cut surface with sulphur powder but cant seem to find mine. I have some phosphorous acid that gets diluted and sprayed on the grape vine to stop white powdery mold on leaves, but I don't know how it would go on a cut surface of the cactus. I also have some peroxide somewhere but again not sure how it would like it on the cut surface. then again a ER dr poured it in my messed up hand after a fireworks accident when I was a kid so it might be ok.