Hello from JustAnswer.
I am sorry that your fiance is not feeling well.
Generally speaking, when someone is vomiting blood, it is time to be seen emergently. Persistent nausea and vomiting also would be a concern that he may be getting dehydrated, but it is OK to try some home interventions if the symptoms were limited to nausea and vomiting. Similarly, vomiting bile is a reflection of the severity of the nausea and vomiting. However, if he is now also vomiting blood, that warrants being checked because it is also possible that there is more bleeding than is apparent in the vomit, as the blood may have passed downstream in the gut.
Blood in the vomit could mean that there is an underlying condition that is causing the vomiting and the bleeding, such as gastritis or an ulcer. However, it is also possible that the bleeding could be related to a ruptured blood vessel due to the repeated vomiting.
If you are in a situation in which he cannot be seen emergently, it would be reasonable to use a medicine to suppress stomach acid until he can be seen, such as ranitidine or omeprazole. It also would be reasonable to limit oral intake to clear liquids.
If I can provide any additional information, please let me know.