
I guess there is no point in giving advice then, what is done is done. Your Grandad is old enough to know his own mind, he probably won't take advice from you.
But, if he will...............A vet will see the pup regardless of age, not an issue, it's just too young for innocultions, but the vet will give worm treatment and flea spray can be used still, try to get your grandad to have the pup wormed with a vet wormer not shop bought, worms are very dangerous for a wee pup and get passed on from the dams milk at that age, so worming is essential at least.
You could try asking him to top up any foods with pasturised goats milk too, bless the wee pup. Your grandad is very naughty to have gone along with this, but he's
your grandad, so good luck.