Where to get heater core and blower motor?

That's why I would take your original to a shop and have them go through it.
How is he sure it's the original? If it's a cheap replacement and it's seen years of use, it may not live to be refurbished. Worth a shot if he doesn't want the Rock Auto one. I almost took mine and filled it up with POR15 and drained it when I replaced it. Almost.