Fr. Wathen confirmed this shortly before he died.  He spoke to me and a few others after Holy Mass.  Apparently Mrs. Welch didn't share her husband's views.

Shortly before Robert Welch died, I made an appointment and was able to meet him in person. Yes, we talked about the Catholic Church. Not only was Mr. Welch a great patriot, but he was also very devout too. He proudly mentioned that President George Washington became a Catholic shortly before he died.

When Mr. Welch was in his last days, bedridden, the good Mr. Robert Koenig (RIP), a close friend of his and long-time traditional Catholic and who worked in an adjacent office, visited him and asked if he could call for a Catholic priest for him. According to Mr. Koenig, Robert Welch replied "yes, and quickly".  And so it was done. It was not Father Wathen as Father did not live in Massachusetts, where Robert Welch lived. I believe it was an older and Polish-American priest who brought RW into the Church. He came out of the sickroom very pleased with the visit. Any reader who knows more details please feel free to add them to this and especially if some of my report is inaccurate, correct me. Thanks.

Robert Welch died Jan. 6, 1985.  Fr. Clarence Kelly administered to him.

That’s what Fr. Jenkins said