No problem.
It'll be good to get an understanding of "if you're not being compensated by salary then what are you compensated with?"
It sounds like you're literally taking the same amount of risk as your boss and for that reason, you should have some share in whatever rewards that come out of the risk taking.
Money to survive has to come from somewhere (i.e. loan, parents, savings, etc.) but it definitely doesn't appear out of nowhere.
Also, evaluate the product. How long do you think they can reach the point where it's revenue generating? In the absence of revenue and cash runs out, will they start to fund raise again? Will all the other expenses be comfortably covered by the current cash pool?
It also comes down to a lot of luck as well. There's really no right or wrong answer here and no one can say for sure if it'll be a success or not. But that's the fun part of life. And trust me, even if you have a normal software engineering job, the success is also always down to you. And the benefits are that you manage to build relationships with other talented software developers and you'd be bringing in money that you can save to start your own venture in the future. Many people have also been very successful starting companies later down in life.
Nothing is ever a dead end. Every path has a pros and cons. It's ultimately up to us to open our minds to see it and leverage it.