From the information that Lopas had managed to find, Rein came to know that just two years after Jakery ran away, both his father and mother were killed by a group nobles who were extremely angry with the magic hating cult. According to them, this cult was slowing dowm the growth of their nation and so they performed a manhunt for any and all members of the cult.
The people without magic were extremely weak at the end of the day even if some of them had a lot of money. So in a very short amount of time, the nobles managed to find and kill almost all the members of the cult and Jakery's parents were included in the list.
Fortunately the two elder siblings that Jakery had were not killed and instead were sent to an orphanage. Not much information was available about them after that. From some of the sources, Lopas guessed that one of the brothers had left the city after growing up but the information about the other brother was unknown.