This tragic story is eloquently written, almost journalistic in style, so I’m a bit suspicious of it’s veracity. What leaps out of the page, however, is the sense that money, things etc are of overwhelming importance to the writer. She tries to win over M with cash and presents - but there are other types of currency, time, eg listening, poetry - a gentler approach that’s not about trying to buy a relationship with the grandson might work,
Also, as a mother of 4 and grandmother of 5, I can acknowledge that one can have a favourite - as I do, but keep it well hidden.