1 200$ per citizen and in a lot of cases less than that and sometimes none?
Nope, there won't be a jump because of that, 1 200$ might be much by third-world standards, but in most countries, it's nothing that would trigger an urge to invest, just as figmentofmyass said. Those that have lost their job are losing much more than 1200$, they won't gamble that money, the ones that afford to throw away that could have invested a long time ago with no stimulus check.

Nope, this helicopter money will not make a dent in the price, but if we get through all this corona shit not that badly scratched and everything is back to normal in two months, then we will have a serious growth. Remember that in order to invest in something people need to have sufficient money and not be riddled with questions and thoughts about unemployment, disease, and death, nobody invests in something because he is jobless and his family is sick!