Hey Jen.
So weird, Me, Zach and Tyler all had that weird virus. It lasted about 8 weeks.
It started as a cold and then turned into strep throat, then after the antibiotic, it turned into congestion and a sinus infection.
We are not that far apart, so must be a virus.
I know for us, we needed antibiotic.
Anyhow, now to your question. I honestly have no idea which antibiotics are safe. I tried to google it and did not get any real answers.
I would call your pharmacy and speak to the pharmacist. They would now for sure.
More than likely they will give him amoxillion for a sinus infection.