Hi Pauline
Can you rescan the photo at all? If you are able to, can you make sure your scanner is set to 300 ppi (refer scanning tut at top of the board). This pic is scanned at 100 ppi and as such, doesn't give us much quality to work with.
I have given it a quick tidy but haven't created one of just your grandfather as I would prefer to have a better scan to work with, and you will end up with a better quality photo that could be enlarged when printed.
If you can't rescan then I'll create a seperate one of your Granddad with the one already posted.
Cheers
Caz