Ravenous, frat-boy-level hunger

Hi folks. I'm new here, and I want to say, thank you in advance for any input. My father has Stage IV melanoma. Three weeks ago, he was on steroids when we learned he had brain mets. A week later, the steroids were discontinued. He's still on Zelboraf. In any event. He is constantly, excessively hungry. We have to puree the food and slide it into his mouth slowly, but he cannot get enough. He demands food of every person with whom he comes in contact. His stomach appears bottomless.

Look; I realize there are a lot of things worse than insatiable appetite at this stage. But since it's been over 2 weeks since his rendezvous with steroids, does anyone know what might be causing this? Thank you and be well.