While the knife in and of itself may basically be crap (it really really is) that is totally irrelevant to it's meaning. Honestly, considering it's sentimental value I'd keep and care for it the same as any old rare Victorinox.
Like others have mentioned its not Swiss made but I think its great that you got your grandfather's pocket knife. I know I'd be made up to have my Grandad's knife the make would be irrelevant.