Should a f'n granny who f'n swears and threaten her grandkids be around them so much?

Every other word outta this lady's mouth is swearing. When this woman buys presents she instantly tells the kids where and how much it cost. My fiancee and me have been struggling with bills we have gotten some help through my parents, but her mother started swearing and complaining and eventually said she'd mail a $25 check in the mail lol. This check never came (probably never was sent) and when we told her she got mad and said that now we just screwed her checking account up. Anyway I'd like to hear anyone's thoughts on this...