Give him another tablet, can take a couple of doses, also use spray around house and new flea collar.
Tablet will kill all fleas on him and those that jump on him, collar will Assisi in that they don't jump on him. But spray house too, we used the flea b*mbs, did whole house in morning, go out and leave it for a good few hours,
Then strip beds, hoover setters, floors, clean down surfaces
And you should be flea clear, then look at a preventative medication, although we find the collar works for about 3 months, then we change it,
Can you tell we do this often, it's the only way we have stopped them, but do it every 3 months,