These matters fall under Good Samaritan Laws— what is your liability if you offer aid in an emergency— and Duty to Rescue—when are you obligated to aid in an emergency. The details vary from state to state, with every state having a Good Samaritan law, but only a few having statutes about the "duty to rescue".
This is the Good Samaritan Act for Texas, covering acts you take to assist in an emergency. Normally a person has no liability for damages they cause while assisting in an emergency, unless they are wantonly negligent or have created the expectation that they will be paid. The exemptions may apply to you (the language in the exemptions section seems a little awkward), though. I believe the short of the matter here is that if you offer help, then the person you are helping is now your patient and you are subject to the same standards of care and subsequent liability as any other patient.
Of course you were intending to do nothing anyway, which makes this a "duty to rescue" scenario. Only a few states have laws explicitly detailing who has a "duty to rescue", and Texas is not among them. The common law approach on this in the US is that no one has an affirmative duty to rescue, unless they caused the situation.
Here's a Texas Law Review on the Duty to Rescue.
And this cites RESTATEMENT (SECOND) OF TORTS § 314 (1965) for the general rule that there is no duty to rescue.
This also appears in this Texas Court of Appeals opinion, which states (emphasis mine):
A party who negligently creates a dangerous situation has a duty to attempt to prevent injury to others if it reasonably appears or should appear to him that others in the exercise of their lawful rights may be injured thereby. SmithKline Beecham Corp. v. Doe, 903 S.W.2d 347, 353 (Tex. 1995) (citing Buchanan v. Rose, 159 S.W.2d 109, 110 (Tex. 1942)). However, a mere bystander who did not create a dangerous situation generally is not required to intervene and prevent injury to others. See id.; see also Restatement (Second) of Torts § 314 ("The fact that [an] actor realizes or should realize that action on his part is necessary for another's aid or protection does not of itself impose upon him a duty to take such action.")."
So as long as you don't create the situation you will not be liable for doing nothing to help. Of course, the social consequences with your family if they watch you do nothing, or with others if said family makes it known to them that you are a doctor, is a completely different matter. But legally speaking you're free to do nothing (and the exemptions to the GSA for Texas suggests this is the wisest course of action for you).