With all due respect to the previous posters, I would suggest that this will require a more serious repair than has been previously suggested.
When I look at the photo there appear to be two tears in the fiberglass, one adjacent to the starboard bolt (assuming the photo is taken from aft looking forward) and one approximately a bolt diameter to port of the port bolt. Since the fiberglass in question does not appear to be a liner, then these are potentially tears in the hull itself. The pattern of the rusty water trail suggests that perhaps these bolts leak (although the starboard one looks like a more likely source of the water).
It seems to me that the only appropriate repair is to unbolt and drop the keel so that you have room to work. (This will also allow you to inspect all of the keelbolts since the typically fail where they pass through the fiberglass) Then grind away the damaged glass to the full depth of the damage, The edge if the area being ground away should be tapered minimally 12:1. I would also grind out an oval shaped flat area, ground down to the depth of several layers of cloth that extends perhaps an inch or so beyond the ground away damaged area. Then it is a matter of building up laminations of fiberglass cloth and epoxy to the bottom of the ground away area, and then laying in several layers of cloth and epoxy to create the bearing area for the bolts. Lastly I second the recommendation that a single thicker SS bearing plate be substituted for the pair of bearing washers.
I am not suggesting that you should not buy the boat based on this, but I would suggest that you try to negotiate an agreement with the owner upfront on how this will get handled (i.e. surveyor confirmation and recommended price adjustment, price reduction based on repair yard estimate, or simply an agreed upon dramatlcly lower price than the boat would be worth otherwise). If you can not get an agreement up front, I would walk away.
Jeff