This question already has an answer here:
My mother's visa is expiring soon. I am intending to take her to USA on a one month trip but I am fearful, her entry into USA when her visa is expiring that soon may cause problems?
Note that I have done that before, she last entered USA when her visa was expiring in about 20 days. She then got another 5 year multiple visa, but now that visa is expiring soon too.
My concern is, would it be ok for my mother to enter USA just 3 days before her visa expires. She will have a return ticket.