This is basically the POV of Leta Lestrange's father, Corvus Lestrange the Fourth, on sending his children to America so Yusuf Kama wouldn't find them. Basically him valuing his son's safety above all else and his daughter's not at all. But then, what else would you expect of him?
He'd send his son to America, Corvus decided.
His sources told him that young Kama was on the hunt, out to avenge his mother. Thus far, Corvus and his wife and children were all unharmed; if Kama had made any attempt to harm them, he didn't know of it. The Lestrange manor was well warded. But he could not trust that Kama would one day bypass them, just as he had figured out how to bypass the wards on the Kama manor. To send his son away, until Kama either gave up or was dealt with, was the best option.
He couldn't place him in the care of a wizarding family there - the ones his family was affiliated with would be obvious targets, and the ones his family wasn't affiliated with would have questions as to why, exactly, Kama was so intent on hunting an infant down, questions Corvus would rather not answer.
He couldn't trust his son to the anonymity of a Muggle orphanage, either. A Muggle orphanage would have no magical protection at all.
However, there were Muggle families to consider.
Normally, he wouldn't even consider it - leaving his only son, his heir, scion of the Lestrange pureblood line, in the care of Muggles. But then, these were not normal circumstances. Anything had to be done to keep Kama from finding his son. Hopefully, he'd be able to....take care of Kama soon enough. But in the meanwhile, desperate times called for desperate measures.
He was currently arranging, through a middleman, for his son to be adopted by a Muggle woman named Mary Lou Barebone.
He had obtained a copy of a list of prospective adoptive parents from New York, along with any information that could be found out about them. Mary Lou had caught his eye, because she knew that magic existed - and hated it.
He didn't know how she had found out about magic. Wasn't the International Statue of Secrecy upheld even more fiercely in America than it was in France?
But he certainly wasn't going to stir up trouble, not when this served his purposes so well.
She knew about magic. She knew magic existed. She got many of the details wrong, but she was right in the basics. And she hated magic with a passion.
She despised all forms of witchcraft vehemently. She would likely rather die than knowingly house a magical child under her roof - or have the magical child die.
And that was what he was banking on.
No one - not Kama, not any of his associates, not anyone in the wizarding community, no one would suspect that he'd sent his son to the care of a magic-hater. Wizards steered clear of Muggles - except Muggle-borns, probably, but that was only to be expected - and especially Muggles who hated magic. The International Statute of Secrecy had been accepted worldwide for a reason.
The Second Salem Church was the last place Kama would look. His son would be safe there.
There was the small risk that Mary Lou would notice signs of magic from little Corvus. But it shouldn't take more than a couple of years to take care of this whole situation, and then he'd retrieve his son, either wiping the Barebone woman's memories or killing her to be on the safe side. No one would notice one less Muggle.
As an afterthought, he decided he might as well send Leta as well. Kama probably wouldn't try to kill her too, being as they shared a mother, but it was best to be on the safe side, just in case. If his daughter was killed by her own half-brother, people would talk. It would look bad. And even if Kama wasn't searching for her, too, if he sent only his son to safety and not his daughter, that would also cast a stain upon his reputation. She could live with the house-elf for a bit in America, he supposed. The details didn't concern him.