How should I handle this situation in a respectful mature way. My mother in-law is...

[jones2mascoll]

...acting like a real B--ch? This is their first grandchild and you would think that they would cut the childish behavior and be their for their son and
grandson. We were on speaking terms until she asked me can she have my son because he is so adorable an I replied in a joking manner naw and we laughed and I thought that was the end of it. She was dancing, drinking and as far as I knew was having a good time when we left she asked when we was coming back so to my knowledge I never suspected anything until the next day when my husband called her and she told him that he better put me in check because she was only Joking with me and I got really nasty with her when she asked me can she have my baby. Every one was sitting their and thought she was playing. Since Christmas She have not called and wished my family a Merry Christmas and her and my husband got into this huge argument and she threatened to call the police on him because he told her to cut the Bull. Now that are back talking she don't ask about my son.