She would need a solicitor to help write the will and provide the wording.
IVA started March 2011, Completed March 2016 and certificate issued 11 days after final payment. It was not always easy but then some of the best decisions aren't.
She should take legal advice as there are ways to do this. For example she could stipulate in her will that if any of the beneficiaries are insolvent then they are to receive no money or their share is to go to the grandchildren or even it is held on trust until the insolvency is over. It would be worth paying a solicitor and explaining everything to them.
Having had experience of this you absolutely need a solicitor to write clearly the instructions and ensure even if put in trust that there is not a small clause on your iva somewhere that allows creditors to receive the money when it becomes available.
In my situation, my mum changed her will to go to my sister and then a subsequent letter was written and signed by my sister to say at the appropriate time she would release my half of my mothers estate. Luckily in was not required during my iva and mum is still with us and will now changed back to 50 50 split.
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !