If after seven days of yeast meds the crop still refuses to empty, other measures should be considered. You can treat a crop that won't empty of solids with a stool softener in addition to the oil.
If the crop remains full of fibrous material in spite of the stool softener and oil, you might need to open up the crop and squeeze out the solids. I've talked several people through this surgery. It's not complicated, but not many are brave enough to try it. However, unless grassy stems are removed in this manner, there's little hope of clearing the crop of such impervious material.