On Dec-24-my father arrived on B2 visa. The immigration officer at Newark airport viewed his ticket, and wrote B2 on the arrival stamp, but didn't stamp any date. During his last visit the 6-month date was noted on the arrival stamp, however didn't happen this time. He was not given an I-94 form during this time or the previous time. Our concern is that he should not be questioned when he visits again. Could anyone please advise.