Just to Substantiate dandakosathi's Claim..and hope it helps for PPL looking for answers..

Dear Mr.***,

Thank you for your inquiry. Your family cannot apply for H4 visa
yet; they have to wait until your H1 status becomes current, which is in
October.

Best regards,

Consular Section

U.S. Embassy

Kathmandu, Nepal

Phone: 977-1-400-7200

Fax: 977-1-400-7281

<<http://nepal.usembassy.gov>>

<<http://kathmandu.usembassy.gov>>