Taxing the elderly when they sell their homes

Why would you take away the right of the elderly to leave their home to their family? Shouldn't it be their right to choose whether they do or not and not be told to invest in businesses etc? Also, if they do sell when they're older, for whatever reason, how much are you going to tax them? I think this will just encourage them to sell earlier and put their funds into potentially unsafe investments as a number of elderly are not schooled very well on investment