They must also be married (and never divorced), straight, bore or adopted the children after the bill is passed (if it is), and there are a few other rules as well.
Among other things, this wouldn’t profit any family, as long as they fed the children, and think about it: What if a Hispanic family wants to have lots of kids? Bet THAT wouldn’t fly.
This is discussed in the pit in the New SRIOD P2 thread.
I don’t think it was mentioned over there, so I’ll mentioned here, that this bill would only apply as an addition to the homestead exemption on property taxes. Texas has no state income tax, so property taxes are generally higher than in many other states. Anyone who does not own their own primary residence would not get anything. Apartment dwellers, and other renters would not receive any relief. The owners of these rental properties would not receive anything, either, since the rental properties would not be homesteads.
So, many of the Hispanics would simply not be eligible if they are renters.
In addition, since there is no state income tax, the local school districts are supported mainly by property taxes. Interestingly, the bill provides a way for the local school districts to get the state to reimburse them for funds lost because of increased exemptions. Essentially, this bill would be just a way to give excess money in the state’s general fund (Texas is realizing a rather sizeable surplus from, among other things, Oil and Gas revenues). Except, instead of doing something sensible, like just allocating payments to the school districts to allow them to lower the tax rates for everyone, they want to go this route.
Personally, I think a better use of the state’s excess revenues would be to expand their Medicaid program, which as I understand it would have an amplification effect from additional federal funds, and improve the quality of life for a much larger portion of the population. By only providing the benefit to property owners, it really wouldn’t change the quality of life very much for those receiving the benefit.
But, like many of the bills being trotted out in Florida and other states with GOP led legislatures, it is not expected to get anywhere in the Texas Leg. That’s not the point. The point is to keep pushing the boundaries, keep reminding their base, and keep people talking about them.
Yeah, this really does seem to target the “right” kind of people: those who own real estate and also are inclined to have a traditional, large family. Let’s see, what kind of family is that likely to be?: one who has accumulated privileged generational wealth and attends a church - exactly the kind of people Texas needs more of - so it makes sense they want to encourage this behavior. 
As a Texan, it is impossible to overstate how low the bar is to be elected to the State Legislature. But “idiot state legislator introduces dumb bill to do some crazy-ass thing” is a lazy staple of news outlets looking for an easy splashy headline.