My first granddaughter was born when I was 50, full time working, so did what I could for my single mum daughter. I took my granddaughter from 7 am every weekday, deposited her at nursery and collected her at 4.30 pm. Then I had her overnight from 6 pm on Friday night until lunchtime Saturday. When her sister arrived I would collect her from nursery and keep her for tea a few days a week. It was a lovely time for us all, but I rarely did full days of care for them. 28 years later I still do minimal grandma duties for my youngest granddaughter - I relocated 160 miles so I could collect her from nursery, cook her tea, play games for a few hours once or twice a week. I would infrequently babysit while my son and his wife went out. My granddaughter is now 14 and we have a lovely relationship, with her being a lovely help to me. I was never ASKED to do the child care, I volunteered for it, probably because when I had my 4 children I received no family help as we lived hundreds of miles away. There is no way that at my age, almost 78, that I would be able to do more than a morning or afternoon childminding, it wouldn't be fair on the child or me. Your grandchild will have a much better day in a professional nursery, where they will be interacting with other children, having stimulating play activities with their assigned nursery staff. Do not feel guilty about refusing to be a carer, offer what you can, babysitting once a fortnight or whatever you can safely do. I think that your son/daughter have been incredibly cheeky to ask this huge undertaking, and I note that you say UNPAID too, that's definitely taking the Michael.