Why do I need a I-601 waiver

[greyson.rizo 3]

My husband had his initial interview, bio, and physical in April 2016 he was told to return after March 2017 for a new physical cause he admitted to smoking marijuana years ago. He remained in Mexico for a year went back April 3rd for new physical and passed he had his consulate interview the next day, he paid fee and was sworn in and asked some questions. At the end they told him everything looked but he needed a new waiver. He was given a form about filing for a new waiver I-601 or 212 and where to send it. He had the I-601A waiver and was approved. We asked for months was there anything we could do or update and have emails and several phone Convo that said no all he needed was a new physical. I also asked them to update online page and they never have after a week. CEAC has been updated with a wrong CDJ # one logged in and says case is at NVC follow steps. I am really confused now. He has never deported, he has never lied or committed fraud or misinterpretation. Do we really need this waiver or both as they are 930.00. I have a child who in therapy because at age 3 now 4 cause she has completely quit talking since her dad left. I can not get a straight answer from anyone about this from USCIS and was wondering if anyone else experienced this.