“Few” means “few people” which means “not many people.” We could say “Not many people are better qualified than he is.” We could restate this as “He is better qualified than most people are.”

It's much better to say Fewer are more qualified than he is for this job. Fewer are more qualified for the job than him. Or He is less qualified than others for this job. Remember few as a comparison is used as fewer. We use it for plurals and countable nouns.