Cover for a picc line

Hi, my mum was diagnosed with bowel cancer with spots on liver as well. She is 74 ( a young 74) always been fit and healthy so this has knocked my sister, mum and I sideways. She is due to have 2nd lot of chemo this week . I have a practical question. Mum has a picc line which is comfortable but the only cover we can find so she can have a shower is very, very tight and impossible to put on by herself( she lives alone ). Any hints or tips?