It depends on several factors, so with the limited information you have included, I can't give you more specific advice. Generally, here's what this person is probably looking at:
A first offense family violence assault is a Class A misdemeanor (TX Penal Code 22.01) and carries up to a year in the county jail and a fine of up to $4,000. However, if a person has previously been convicted of family violence assault, then a subsequent arrest is charged as a third degree felony in Texas, carrying 2 to 10 years in state prison and a fine of up to $10,000 (Texas Penal Code 22.01(b)). This charge can also be a felony if it's been alleged that this person either caused serious bodily injury or used/exhibited a deadly weapon during the commission of an assault of a family member (TX Penal Code 22.02). Of course, if this person has prior felony convictions, this charge could be enhanced to a second degree felony with up to 20 years in prison.
You would need to provide more details to get a better answer, but the best idea is to speak with a local criminal defense attorney who handles family violence cases in order to get a better idea of what kind of punishment is realistic here.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.
In addition to the information provided by Mr. Walcutt, you should be aware that a first time offender in Houston would be considered for probation if the assault was not severe. Moreover, it could be enhanced with a prior assault that involved family violence as shown by proof and not by a prior finding of family violence. In other words, if the prior case was a husband on wife, girlfriend on boyfriend, child's parent on other parent, etc. but there was no finding of family violence - it just was not alleged or found - then the case could still be used to enhance a subsequent case to a felony with proof at trial of the facts of the prior. (Many people do not understand this but there is a case directly on point.)
Also, family is defined in the family code and can include dating situations, living together, having a child together, as well as the traditional meanings of family.