thanks for your replies. perhaps I did not phrase my initial question well, but redro's reply captures the line of my thinking. Yes, my parents prefer to stay in India at the moment, they are comfortable in their space and have a system of services they know about and can rely on. But the future is unknown so the status of staying in India can change quite rapidly. I understand what some posters are saying about why apply for a GC when they are doing well in India, or higher health insurance expenses in the US vis-a-vis what they can find in India, but when time comes maybe they might need the presence of a family member. My parents have also said that if one of them passes away, they don't want to stay in India by themselves - which is independent of their health. So one path or the other, I have to prepare for my parents staying with me. To 'thread the needle', I like the idea of pausing the application once their petition is approved and hopefully this cuts down on the time it takes to move to the US.
I will investigate the costs of their health care
thanks
-S