זֶה שֶׁמַּאֲכִילוֹ וּמַשְׁקֵהוּ, מִשֶּׁל אָב וָאֵם, אִם יֵשׁ לוֹ. וְאִם אֵין לָאָב, וְיֵשׁ לַבֵּן, כּוֹפִין אוֹתוֹ וְזָן אָבִיו כְּפִי מַה שֶּׁהוּא יָכוֹל. וְאִם אֵין לַבֵּן, אֵינוֹ חַיָּב לְחַזֵּר עַל הַפְּתָחִים לְהַאֲכִיל אֶת אָבִיו.
הַגָּה: וְיֵשׁ אוֹמְרִים דְּאֵינוֹ חַיָּב לִתֵּן לוֹ רַק מַה שֶּׁמְּחֻיָּב לִתֵּן לִצְדָקָה. וּמִכָּל מָקוֹם אִם יָדוֹ מַשֶּׂגֶת, תָּבֹא מְאֵרָה לְמִי שֶׁמְּפַרְנֵס אָבִיו מִמָּעוֹת צְדָקָה שֶׁלּוֹ. וְאִם יֵשׁ לוֹ בָּנִים רַבִּים, מְחַשְּׁבִים לְפִי מָמוֹן שֶׁלָּהֶם, וְאִם מִקְּצָתָן עֲשִׁירִים וּמִקְּצָתָן עֲנִיִּים, מְחַיְּבִים הָעֲשִׁירִים לְבַד.
- If the parents can afford it, then the child spends the parents’ money for their food and drink.
- If the parents cannot afford it, but the child can, then:
- According to the Shulchan Aruch, we force the child to pay according to what he is able.
- According to the Rema, he is not obligated to pay more than the amount he would normally give to tzedakah (though if he can afford more but doesn’t, a curse should come upon him). If there are wealthy and poor children, the wealthy ones should be the ones to provide for the parents.
- If neither one has money, the son is not obligated to go beg for money to feed his father.
Your question, therefore, would apply only in a case where the son has money and the father doesn’t, and it would apply only lechatchilah according to the Rema but even bedieved according to the Shulchan Aruch.
The Mefarshim explain the problem that this is a Mitzvas Asei with its reward written in the Torah, so how can Beis Din force him to pay at all. I’m not going to transcribe them here, but you can see them inside at the link above. Basically, the Taz (§6, end; begins last word on the page and continues onto the next one), quoting Tosfos, answers that Tzedakah is different because it also says a prohibition of “do not hold fast your hand.”
It would seem, then, that if we’re going to apply the prohibition by Tzedakah to Kibbud Av, then in that one case, we would force the son to give up even everything, according to the Shulchan Aruch (and according to the Rema, he gets a curse if he doesn’t).
Now to nitpick on your question.
BTW having awe of one's parents is also a positive Mitzvah that is very close to a negative as the Torah says "ארור מקלה אביו ואמו".
Having awe of one’s parents is a positive Mitzvah. Period. Not to curse your parents is a different prohibition, and it’s learned out from Shemos 21 and Vayikra 20, where it says that one who does so gets the death penalty. That one gets a curse, as should be clear by this point, does not make something a prohibition. No need to resort to Devarim 27.