It is an unrealistic assumption that no one would realize 1 Trillion.
That said, if you are simply interested in what happens to inflation if money supply increases significantly, your 1 Trillion is not that much after all. The below shows M1 (~ currency, liquid demand / savings deposits). The definition changed as @1muflon1 pointed out correctly but nonetheless, M1 (prior to the change in definition) went from 1373 in Dec 2007 to 4000 in Feb 2020, yet inflation was very low throughout the entire period. Money supply generally has a large impact on inflation - all else equal though. Eventually, if money supply increases enormously, you will end up with hyper inflation as seen in many countries before.
It also does not matter if you use your money in your bank account or not, because your deposit is a liability of the bank. For example, your bank may use the money in your deposit account to make loans to other people or businesses. Maybe I am wrong, but I understood that question as a purely hypothetical example without much attention to details - with the goal to understand what would happen to inflation if money supply increases a lot. If we use the unrealistic example of one person gaining 1 Trillion, and assume it's just possible, there will be a bank, with a lot of newly added deposits. For this unrealistic example, one should in my opinion also ignore all regulatory issues with this (it will have a significant impact on a lot of metrics that banks need to compute). In any case, the money will get into circulation indirectly if it is sitting on the deposit account (which is why I wrote it does not matter). The exact impact on inflation is pretty much impossible to determine, because an additional 1 Trillion in deposits in a single bank just don't work. The "recent" spikes in inflation across the globe show how difficult it is to explain inflation ahead of time even in real world settings. There was very little agreement among professional forecasters on the magnitude and path of inflation.
Side remark, the government does not decide money supply, the FED does. The government has some influence like the president appoints the FED chairman but ultimately, monetary policy decisions lie in the hands of the FED only. Trump appointed Powell and later said that he is “not even a little bit happy” with his appointment of Jerome Powell.