Any advice much appreciated..

My grandfather was diagnosed with stage 4 bowel cancer and has recently started chemo using Folfiri. The first 3 days he was fine when on steroids and anti sickness tablets and now on the 4th day, when steroids are done for this round, he has gone downhill.  
Voice is hoarse, threw up yesterday and lost all power in his legs. 
Naively, we had thought that he may not react badly as the first few days were great but now it's hard for everyone in the family and I would love to know if anyone has had these symptoms (or others), how long they last?