Replacement eyepiece for a Tele-Science scope?

I'm hoping that someone here has an idea of where to find a replacement eyepiece for this scope. My son is 12 and at an auction he convinced me to bid on it, it wasn't something that I had checked out and from what I could see it looked ok but upon winning said bid, i saw that it didn't have an eye piece. It is a Tele-Science Astronomical Telescope F=500mm D=50mm and its on its original tripod.

The issue I am running into is that all of the eyepieces I am finding on amazon are 1.25" and the eyepiece holder on the scope measures 1" on the inner diameter.

Any help/advice/direction would be appreciated (excluding telling me to buy another scope, its his first and he is pretty jazzed that he won the bid)

Thanks!