The gofundme is IMO fraudulent.
"For 30 years, my sister-in-law Irene has lived in Britain after arriving here from Singapore."
Total lie!
She lived in Britain from 1988 to 1992, and then from 2003 to 2005, then from 2013 to 2017.
That's ten years out of thirty.
Further, for all intents and purposes, she separated from her husband in 1998. That's two decades ago!
SHE made the decision (if that really is the reason) that it was more important to stay in Singapore and look after her parents than care for her children in Britain. She could easily have found carers in Singapore - it's much cheaper to do that there than the UK.
I'm honestly curious about the basis on which she entered the UK in 2003 and 2013.
When I got married, we applied (in 2002) for a visitor visa to the UK and it was declined on the basis that as husband and wife, we intended to live together and therefore we did not require a 'visit', but rather 'settlement', and we had to apply for that.
So it seems to me that she must have claimed in 2003 and 2013 that she was 'visiting her children', because if she had said she was coming because of marriage, then she would have acquired the right to remain.
So by remaining here she is in clear breach of her visa requirements and would have known that the minute she first arrived.
The idea that a family is being torn apart is nonsense - she is entitled to live in Singapore and visit her family (who must now be adults) in the UK, but the operational word is VISIT. The right to live with her husband sailed, pretty much when her husband left her in 1998 to go and live in the UK with the kids.
And I don't like the 'grandmother' description, she is 53 and applying to be with her husband, the fact she is a grandmother is irrelevant. My children have a 'grandmother' in a foreign country who could never settle here - we go and visit her. There's no problem with this.