Can anyone let me know their experience of steroid 'highs and 'lows' please.

My dad is currently on chemo for Bile Duct Cancer with mets to several areas. He is given steroids on the day of chemo and for 3 days after, while he is taking them he feels reasonably well, but as soon as they are out of his system he feels awful and is in a lot of pain. He is on a 3 week cycle with chemo on days 1 and 8 then nothing for the next week, during this week off he can hardly move.

I realise that they way he is on the steroids is because of the tablets but does that mean if he wasn't taking them at all he would be permanently like he is during the 3rd week? Or does the constant on and off make him worse?

Any advice would be much appreciated, thanks x