Sorry for your loss.
The forum is a great place for help during this time and I know members have helped others who have faced what you are going through.
Absolutely follow Foggy advice.
You can go to here https://www.gov.uk/inherits-someone-dies-without-will
for some help around identifying what you might have to do next.
I apologise for the wording now - it comes across as impersonal but it reflects the legalities,
You are not liable for your husband debts - you are likely to be responsible for being the Executor and working towards settling any debts from your husbands estate.
That means that the Insolvency Company will need to clearly identify to you what they believe is owing.
Given the recent Creditfix court case, I would suggest that when the Insolvency Company contact you, that you get confirmation in writing that they have contacted creditors for permission to proceed to act on their behalf.
Based on what you have identified, it is entirely possible that some of all might not wish to recover anything but a lot of that may depend on how much was owed.
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.