:sl;
Console her by saying everyone has to go back to Allah. tell her that her mother 's gone and So we will, later one day and we will be reunited with her Mother again FOREVER in Jannah inshallah if we die in eemaan , so lets try to be as pious as possible.
Also console the loss of a Mother is big loss which Only time will make it heal iow with the passage of time we will come out of that pain , inshallah