Praise be to Allah.
May Allaah reward the questioner with good for his eagerness to seek halaal provision. If he continues to do so he will succeed in sha Allaah in this world and in the Hereafter. Allaah says (interpretation of the meaning):
“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty).
3. And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allaah, then He will suffice him. Verily, Allaah will accomplish his purpose. Indeed Allaah has set a measure for all things”
As for working in this job, it is haraam so long as the restaurant sells haraam things, even if the one who holds this job does not do the selling himself, because he is helping with something haraam. Allaah says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment”
Imam al-Jassaas said in Ahkaam al-Qur’aan (2/429): The apparent meanings of the words of Allaah “Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety)” indicates that it is obligatory to cooperate in everything that is obedience to Allaah, because birr (righteousness) is obedience to Allaah. And the words “but do not help one another in sin and transgression” mean that it is forbidden for us to help others in disobeying Allaah. End quote.
And Allaah knows best.