I'm sorry, but seahorses are not something where they have fry and the fry grow up along side the parents and "reappear" at a larger size - with the exception of dwarf seahorses and the rare case where someone has a very specialized setup. If you cannot see the fry, the fry are gone. They are dead. They have been sucked up in filters or eaten by corals, bristleworms, aiptasia, large amphipods, shrimp, seastars, fish, etc. This isn't to say that fry are not tiny enough to "disappear" in a well planted refugium for a while, just that unless the refugium is "fry-safe", there is very little likelihood that the fry will ever "reappear". If one does, buy a lottery ticket.
If you would like to try your hand at raising fry, do some research on the specialized fry rearing setups that seahorse fry need, and then when you're ready, buy your boy a female.