It would seem odd if the DD didn’t mention a break-up, if that was the cause. Seems like an easily believable excuse, “Mom, I was doing very well until Tom and I broke up. After than, I couldn’t concentrate or study.”
Has the mom come back? I think she was venting because she was really depending on that “free ride” to cover college costs. Understandably she is mad and upset, but unless the award can be appealed, it’s now water under the bridge and Plan B needs to happen.