He is about 2.5% better off in the low inflation period in terms of dosas. This is a long winded way of saying that inflation is the silent killer because it eats into pensioners’ principal, even while they are deluded by high nominal interest rates into thinking they are getting an adequate return.
Indeed, with 10% return and 10% inflation, the deposit is not giving you any real return net of inflation, which is why you can buy only 2,000 dosas after a year of investing, the same as you could buy before you invested.