go thru the boat with a fine tooth comb, if you feel confident, if you know what your looking for, if your confident in your findings make them an offer, its going to need a bottom job soon, that hole is going need to be inspected and fixed, when ya do the bottom job the zincs need to be replaced, what condition are the thru hulls? how old is the standing rigging? what condition is the running rigging? the sails? what condition are the instruments in? whats the overall condition of the boat?
all questions only you can answer, and if your not sure, find some one who does to help ya, maybe a local old Salt there at the marina
Steve