It is possible but we know in gambling luck isn't always on our side. So what if you loss 1week or more and you have family. You won't eat then, will you take a risk? Not a good idea in any angle. Daily expenses should come from a stable job that gives you a steady income. Not from a thing that depends on luck.
You can’t just assume that it’s impossible because you feel the income coming from gambling is not always stable but you should know that different people to how they plan and how they manage themselves. I know of a family man that lives his life on gambling, no other source of income and he has a kid. I sometimes imagine how he survives with this but I know so well that, that is what he does for a living and he is a professional gambler.
From my discussion with that man I realized that not all gambling is a game of luck. There are some that requires skills and professionalism and a lot of work is always put into such to bring about consistent earnings. So anyone that desires to spend a living from gambling might have to go through that process by learning, studying and doing all that is required to keep winning.
I am so happy to know that the gambler you know shared the little secret with you. Many people, who assume that it is hard to make constant money out of gambling, mostly have no idea about how it works. I am not totally in support of that, but for those who cannot get a job and need a source of income, they can decide to make it one and learn all that is required to achieve this.
I gamble for fun and I am not an advocate of people who depend on gambling to take care of their needs, but then, if as a gambler, you feel you can achieve this, then go ahead. Who are we to judge? Gambling for money will not be so easy because of the uncertainty in the game.