According to the product description:
Within 12 hours of application, 98-100 percent of fleas are dead. The second active ingredient, pyriproxyfen, is an insect growth regulator. Once a female flea lays her eggs, pyriproxyfen works to prevent the eggs from hatching, ending the flea life cycle.
So it she treated him 2 weeks ago, you should be okay.
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."