Is it worth a rescue?

Hi there,

it's not worth spending too much, but if the mirror is in good order, it would make a fine starter scope. The very cheap and nasty scopes start around D=76mm, and often boast great magnifications, these scopes are virtually useless. The size of the mirror is the most important factor, and at 114mm, your grandson will have many hours of pleasure observing the moon and planets.
Eyepieces can be found on ebay very cheaply, but be sure to get one with the correct O/D they come in 0.96 in, 1.25 in and 2 inch. I expect your scope will be 1.25" I suggest you should buy a maximum of two eyepieces (around 30mm and 6mm) and a barlow lens. These will give you magnifications of 30X, 60X, 150X and 300X.
If you require any further assistance, please don't hesitate to ask.
Kind Regards......Dave