My son is 3 years old, has seizures and is very congested.?

I was told that giving him Benedryl would increase his seizures. The doctor said to give him Claritin instead, but that does nothing for his congestion. If anyone can recommend or tell me if there is anything else out there that I can give him, I'd greatly appreciate it. I've tried nasal rinsing and suctioning, but it's only a temporary fix. I've told the doctor about the Claritin not helping, but he said that's all they recommend to children with seizures. There HAS to be something else out there!