hi,
it is very simple, your kids can get admission in any school in the us.
where do you live? do a lot of research before sending him to a school. some school districts are very good and some are average. usually the local newspaperes or parents organiztion do the grading of school districts and particular school. if your son is extraordinary he can go to charter schools.
my suggestion will be:
1. if you live in an apartment dont go for a cheap areas. rent an apartment in an a nice and crime-free area.
2. dont send your boy to a private schools. since he is just six it is not a concern but in most of cases those who go to private schools they are either offsprings of rich people or they had problems in public schools.
3.public schools are free in the us but you have to give atleast two hours for him to help him for reading, writing, math and more.
4. please consult the local school, they will give you proper counselling.
5. consult local nepali friends who have school going kids.
6. you look very concerned parents. i have seen nepalis here who would not take their kids to movies, zoos, museums, libraries. they think these activities are waste of time and money. i will say if you are in the us adopt an american life.
7. your boy has a good future here, the only endevour you have to keep doing from today is to get a HARIYO PATTA.
8. very very good luck for you and your boy.