That's a rosy tinted view of India!
If your parents / grandparents can afford it, then you farm out childcare to the ayahs. British rule may have ended, but the class system is still going strong. Nannies are a way of life for those that can afford them, and a status symbol - so childcare isn't, as it so often is in Britain, tied to needing two wages so much as perhaps wanting two wages, a woman being a professional in her own right, or even, not wanting the burden of childcare herself. Ayahs are cheap - a well qualified and experienced nanny is less than £100 per month. Hiring a local woman with a good reputation, much less than that!
Current research says that dementia rates in over 60's is slightly higher than the UK, and a little lower than the USA - so clearly continuing childcare doesn't make you more or less likely to contract dementia. https://www.fic.nih.gov/News/GlobalHealthMatters/march-april-2023/Pages/new-estimate-dementia-prevalence-magnitude-india-challenge.aspx
Other things that are very normal in India are malaria, TB, pneumonia, IHD and other heart diseases, extreme malnutrition, poverty and living in slums, and an infant mortality rate of 26.619 per 1000 births (the UK is 3.7).
And the main reason that grandparents (mostly grandmothers) look after their grandchildren is so that youger adults in the family can both go to work to support the entire family including the grandparents because millions have no pensions, no savings, no homes, no healthcare - and nowhere else to go and nothing else to do.
Something like 27% of Indias population live in extreme poverty and hunger - living on less than £1.60 per day and 60% of the population live on less than £2.50 per day. One even more stark figure - the welath possessed by the richest 16 Indians is equal to the total amount of wealth of the 600 MILLION lowest income people.
That doesn't include the father of a certain PM's wife, who with a mere value of £4.3billion only managed to get to number 41 on the list.