As noted, then the husband is presumed to be the father:
Texas Family Code - Section 160.204. Presumption Of Paternity - Texas Attorney Resources - Texas Laws
The rules on the challenge are contained here:
Texas Family Code - Section 160.308. Challenge After Expiration Of Period For Rescission - Texas Attorney Resources - Texas Laws
Since the bio father did not file within 60 days, he can only protest on "the basis of fraud, duress, or material mistake of fact." Since you state he knew he might be the father, that would appear to remove that claim. However, since the child is only 1 year old, he would seem to be within the 4 year limit to file.
So, if the bio father wants to challenge the husband's paternity there is a possibility he can do so. He should consult an attorney to determine his chances.