Klipsch and various aftermarket folks sell grill cloth and such, in case you botch the effort and need to try again. Given the age of those, and assuming you plan on keeping them and listening, you may also want to consider re-capping the crossovers. Those degrade over the decades, and a new set will restore your speakers to original condition. I did so on some old Heritage; it was inexpensive, and worth it.
Sorry about your father. Think good thoughts while rawking out to his Cornwalls.