As long as it’s architecturally and aesthetically the same can he, say, upgrade the electrical and the plumbing systems, wire for cable and internet, and, most important, upgrade from 1936 earthquake and fire codes to 2018 codes? I would let him do that if I were SF. Incidentally, if he does this right, and with the publicity and the famous architect, he might get more for this rebuild than for the McMansion he was originally planning.
