Are there consequences for someone falsely accusing you?

My life long friend is going through torcher since him and his ex wife split up. Now he is remarried to a great Girl! They are still going through a fight for his kids. In the last 6 months his ex has called CPS (child protective services) 49 times, all unfounded. To the point the case workers are annoyed because they feel there is more important houses they should be at, rather than waisting there time there. (It really is a good household) When those fell through, she accused his new wife of beating her youngest son and told the cops that there was brusies and welts on his bottom. and had her son (who has medical problems, she(the ex) wont treat) say the new wife hit him. The cops got there said they had to look at him on his bottom, ( which she fought until told she had to)...and nothing. The cops was upset. Now that all this fell through she has upped the allegations by saying now ual abuse. Seriously....isnt there a way to make her stop. She just wants him to split with his wife and sign over the kids completely. He is about to head to the luney bin, if this keeps growing. If she has gone this far...whats next? How can we stop her, or can we? PLEASE HELP!