Would you please give me a recommendation of the best type of bitters for diabetics? And, what could be done if it's sinus?
If you can find some bitter melon on line this would be the best for a bitter in his case. Not only is bitter melon bitter, but it also functions similar to insulin to drop the blood sugar. This can help reduce his insulin needs, which is important since most of the serious side effects of diabetes come from insulin, not the elevated blood glucose.
As for the sinuses here is an old post on sinus infections: