With all due respect, this is another huge stretch. If the person does not drink alcohol, then the first statement is nonsequitur. It would be the same as saying "I did not axe-murder my three next door neighbors till the blood test." There is no point in mentioning it if you don't do it. By all reasonable construction, the first sentence clearly implies that the person does drink alcohol, generally. The only point of the sentence is that he did not before the blood test. We are absolutely led to believe that he did at some point after the test.
As to the "brothers", Jesus Himself loved calling people brothers and they were not blood relatives; he in fact taught us all to do the same. In large families there is a mixture of cousins, second cousins, half brothers, milk brothers, and of course bolld brothers. It is natural to refer to all of them collectively as "brothers".
Of course with this interpretation, we are now forced to throw out other Bible verses, such as the following:
Matt. 13:54-56 : "54 Coming to his hometown, he began teaching the people in their synagogue, and they were amazed. "Where did this man get this wisdom and these miraculous powers?" they asked. 55 "Isn't this the carpenter's son? Isn't his mother's name Mary, and aren't his brothers James, Joseph, Simon and Judas? 56 Aren't all his sisters with us? Where then did this man get all these things?"
So, first Jesus is identified as the carpenter's son. Then He is identified as the son of Mary. Then, His four half-brothers are specifically named, along with the fact that He has sisters. But we can't have this can we? No, we have to make a drastic veer in mid sentence no less. Son of a carpenter, fine. Son of Mary, fine. Brother of James, Joseph, Simon and Judas, NO WAY! The Church doesn't allow this family relationship so we just interpret it out of existence. No problem. This continues to floor me. :)
"So, first Jesus is identified as the carpenter's son. Then He is identified as the son of Mary. Then, His four half-brothers are specifically named, along with the fact that He has sisters. But we can't have this can we? No, we have to make a drastic veer in mid sentence no less. Son of a carpenter, fine. Son of Mary, fine. Brother of James, Joseph, Simon and Judas, NO WAY! The Church doesn't allow this family relationship so we just interpret it out of existence. No problem. This continues to floor me. :)"
Actually, your interpretation comes from a Western European context. In the east the term brothers or sisters could as well have meant members of the extended family. There are parts of Greece where this is true to this day. There is tradition which says these people were cousins and another which holds that +Joseph was a widower with children, thus the 1/2 brother business, the people of course assuming that +Joseph was Christ's father. Again, you must remember that the men who decided what was to be in the canon of scripture believed in the perpetual virginity of Mary and saw no contradiction at all in these passages of scripture you present with that belief. That's because they lived in the cultural context the scriptures were written in.
God, of course, would know all of this so he gave us Holy Tradition and the Fathers so people 2100 centuries later in another culture entirely could understand what was written and not assume that the culture they live in and the language they speak are and were the only languages and cultures which ever existed. :)
The statement "I did not drink alcohol till the blood test" is a necessary statement to validate the blood test. Even if I never drink alcohol, it is necessary to make if the test requires such period of abstinence. But the statement "I did not murder my neightbor till the blood test" is nonsensical because there is no relation between my blood and the murder. Perhaps my use of "I" in the examlpe is misleading because of course I know about myself both before and after the test. Remember, it is Matthew, who does not know the intimate life of Joseph and Mary speaking to us. It is exactly analogous to a nurse speaking to a doctor: "the patient did not drink till the test". The nurse knows the condition before the test because of the chemical analysis. The nurse does not know, and is not interested, in the condition after, so he is not speaking about the after. Matthew knows the condition before, because he has a statement form Joseph (for example) made at the time of Jesus's bith. He does not know and is not interested in the condition after that.
Son of a carpenter, fine. Son of Mary, fine. Brother of James, Joseph, Simon and Judas, NO WAY!
But this is consistent with the fact that a man has one father and one mother, but many relatives of the same generation. "Brother" can be used expansively; "mother" cannot. Besides, "son of carpenter" is indeed used imprecisely here, just like "brothers" is used imprecisely.