Can Marinol Be Taken Along With Other Medication?

My husband is being treated for cancer of an unknown primary. It acts like colon cancer. He is now given Erbitux and later will add Iritonecan. In the mean time, he vomits a lot due to the cancer pressure on the outside lining of the small intestines. The drugs that are given to him are Avitan and Ambien to control nausea and sleeplessness. Can he take Marinol while taking these 2 drugs? He took Zofran, and Reglan but still vomits.