Yes, I agree that it might be a long stretch that the Mother may have been on the autism spectrum.
However, I was just trying to introduce another possible angle regarding why such a seemingly insensitive comment may have been made. Some people on the autism spectrum can have difficulties with being able to empathise and consider things from another person's perspective. They might say what they think with no real understanding that certain comments might be hurtful. If this was the case here - and again I agree this might be a long stretch - the Mother might have just been saying what popped in her head with no intention to hurt her daughter's feelings.
We will never really be able to know based on one small article. It could well be that her actual words were misrepresented. Or that these were her words, made with the best of intentions but expressed insensitively.
If these were really her words, I still don't think that this was the best thing to say in her daughter's best interest. I think it would have been better to have focussed on his behaviour rather than any possible shortcoming on the part of the daughter. Mother could have given any number of examples to highlight her sense that he was not a good match .. he stood her up, he was non-supportive, he didn't listen/show interest, he was lazy, critical, bad tempered, violent, etc. .. The daughter, perhaps blinded by love might have still gone on to marry him and may have told Mother that she didn't want to hear anymore against him. In such a scenario, Mother could say that she had said her bit and would say no more. Then if/when things went pear shaped she (ideally) would be there to support daughter and daughter might realise that Mother had shown tough love in her best interests .. and still be able to emerge with self esteem still intact.
I agree too that such a comment would be good ammunition for an abusive person to use to isolate and belittle. Perhaps in the way of 'even your Mother doesn't care for you she told me you were not good enough for me .. I don't want you to have anymore to do with her, she criticises us both. Then again your Mother was right, you aren't good enough for me, I could have married a much more good looking girl but I settled for you ...'