Is the objective to start with a property and leverage to buy more and more until they have enough cashflow to live off of it?
For some, yes. Other people have different objectives, there are no wrong answers as long as you have a goal and work towards it.
get roughly 200k to invest into a million dollar property.
Seems like a bad plan. Why are you set on a million dollar home? Are you expecting it to appreciate rapidly to be worth even more? do you expect to find a million dollar home that will cashflow enough off of a conventional loan to make a dent in your parents finances? Do they expect to live in this later, is that why you are set on a million dollar home?
Why not take the 200K and buy several homes of lower value that will cashflow? Why not use the money to buy an apartment building with several tenants?
I guess my point is, 1 expensive home will not cashflow enough to get where you want to go, and because that property is likely already in great shape there likely isn't a way to force appreciation. Without forcing appreciation it will be years before there is enough equity to leverage that property into more property.
I think you need to do a lot more research before pulling the trigger on anything.