Someone's mom has 4 sons North, West and South. What is the name of the fourth son.

The fourth son could be named anything, not necessarily only "East."

Maybe "Someone" is his name.

Teachers: We supply a list of EFL job vacancies

Although your question has many grammatical mistakes, yet I can guess that the fourth son's name is 'What'.

Good one! That's a possibility too. Especially for such riddles.