192.com does not have just old information.
If you belong to FindMyPast you can get information on the ER's, or you can pay for it elsewhere.
Facebook is not illegal.
Was Mabel born in 1911 or at the end of 1910. You have put that she died in 2002, is that an exact year or just a guess? If you get her birth certificate, then you can look for her death more precisely, as there are many women called Mabel Ward. There is a death in January 2002 in Blackburn - is that her (born 31st January 1911)
It is more likely nowadays that she will have left a will, so if you know when she died you can try and find that, download it, and look for information about her children.
There is a will for a Mabel Ward died 10th January 2002. Worth investigating further.
https://probatesearch.service.gov.uk/#willsI disagree with your assertion that looking for living relatives is family history. If you make contact with them, you are 'living' with them, that is not history.
On a personal level, if some one who does not know me calls me 'my friend', I would find that extremely annoying in so many different ways.