How do we use this amount?

buy a villa or something like that and then save the rest of the amount as fd .. so u can live with the intrest which u get from it.. great idea?

Let your parents make the decision of how they would like to spend the money. They might want to invest it in a kind of business which will keep them busy and active in their retirement. They might also want to give some share to the children. It is up to them really.

for you, you can look for someone to share the rent with find someone you can trust so you don't end up regretting it I am sure your parents wouldn't mind if you can't afford to buy them a house living in the city for old people is most likely not what they want there must be an affordable house in the country side that they can get they can still save money for emergency that way

As I read your post. You said that your parents had a big amount of money. But you didn't know how to used that money, right? Then, you want to build your parents a big new house. I suggest to make it for that purpose...Because house did not depreciate it's value and will be appreciate year by year...That maybe the good investment that you do for your parents...

Well if your parents are dreaming hard of a bigger new house and you and your other family members have that many and want your parents to be happy then I would say weigh up your options. Some people would get them what they want to fulfil their dreams. Others would go the more logical route and get their own accommodation sorted out first instead of high renting prices for apartments and so on and then maybe just give the remaining cash to their parents to put towards a house or even to fix up the one they have. It's a hard one to call really it comes down to you and your siblings state of minds on the matter. Me personally if my parents wanted it so bad I would give them what they want but thats just me, id do anything for my mom and dad in a heartbeat if its within my power to do so.

yes you can build house for your parents. You can fulfill their dreams by doing in their real life it self.

Wow! Big amount? And you do not know what to do with it? Can you share me some? Kidding aside my dear, Why not improve your parents house, purchase a house where you can live in the city. Yes, that is more practical. Rather than rent when you can actually have a house to live with and you can say your own. Of course, your parents deserves to live with a bigger house. But, what's the use of bigger house or wider one when you are not there joining them. That would be more sad on their part. So I guess, you just need to improve the house.

Not knowing all the circumstance i don't want to give u any advice. I will say that instead of spending all of it at one time put some in a savings for later when they might need it worse. Rainy days do come along when we least expect them.