The hoover is your best friend against fleas - keep on hoovering things every day x The household sprays (the ones from the vets anyway) work very well - but i've found the cheaper alternatives don't work, however that was about 6 years ago that my neuters got them (they don't go out roaming now lol) the cheaper stuff could be better now than it was but i personally would stick to vets stuff unless anyone else on here knows of better
oh, and yes keep using flea comb on him, even for a few days of not finding any, they're sneaky so carry on until you're sure xx
Welcome by the way

xx