What can I do if my landlord is asking me to vacate the flat without any prior notice?

I moved into a flat in may 15, 2023 and was asked today oct 17, 2023 to vacate in a month. The landlord is selling property (which was not informed to us when we rented). the new owner says his brother will stay at the flat. its mentally exhausting to search and again shift. we have a 11 month agreement with the old owner. The property will be registered to new owner in Nov.-dec and he wants it vacant as otherwise it can’t be registered. The area we are in has very less houses at this time and rents are v high due to that. houses get vacant after school term ends. we already requested the owner saying its v difficult for us as we just shifted. Plz advise how we can get time from them and is there any rule protecting a tenant from this situation?