She can, but I would question the wisdom, long term. Your IVA payments come with no accruing interest charges -- the credit card debt has a very high interest rate. Your mam would also be taking on a debt which would probably take longer than your IVA term to repay --- what if she were to run into financial difficulties in the next few years ?
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014