They make some of the tubes still because of restoration projects like your hubby.... There are sites on line for em. Capacitors will always be made.... Especially for high voltage equipment. Switching and gear like that. Again Give Heath kit a try. They are online still they were bought by Radio Shack and Radio Shack was bought by Tandy...
My dad was an inventor... I spent many hours hanging with him in junk shops looking for Electronics components. So My ennd is just a GoFer... Give me components and I can put it together...
deb