Talk to your dad's doctor about the anxiety. Depending on what he's been given, it's possible he can take a lot more. I'm on pretty regular anxiety and depression medication, and my very sensible psych upped the doses for some of them during my cancer treatment, because obviously that's going to push the boundaries a LOT! If I can be prescribed as much as I get, you can certainly question if your father can be prescribed more regular or a higher amount dosing. If it's for anxiety or panic attacks, I find that by the time mine break through, they are a lot harder to stop, and it's better to keep them in check up front if possible. Cancer is scary. Might as well go ahead and get the anxiety under control if you can ... enough of the rest feels out of control as it is. I'm NOT a doctor, of course, but I've been dealing with panic attacks for near twenty years now, so I have some experience in this area. Ask. It is always worth it to ask.