So very sorry ….this is devastating news for you and your family. Whilst I hope she will have more time, for you and your son and the GC's it is not going to be easy. All I could suggest is, and I am sure everyone will, make sure the time she has left is a good and positive as it can be and you can do thing together as a family to make some lovely lasting memoried. To this end, I would imagine you are all doing the suggested things ...keeping a 'memory box' for each child, from their parents childhood, their own growing up, the marriage, each birth and milestones, with whatever items you may have (hair, a particular painting, etc of things the children have done or made over the years...and please do get in touch with a child bereavement counsellor (for yourself, so you know how to deal with each stage ...there is no need for your DIL or your son to know if you would prefer to do this alone for yourself for the moment. So hard for you and my thoughts are with you all 