Hi and welcome.
I think an IVA may be useful for your son. His income certainly seems to support this. Is his wife going back to work when her maternity leave finishes?
I personally wouldn't recommend a consolidation loan because it is a) secured and b)more debt which has to be paid back. The credit cards would still be there and there would be the temptation to use them again. I speak from experience as this was what I did a few years ago and still ended up in an IVA.
I recommend that he speaks to an Insolvency Practitioner as soon as possible to sort out his options. There are several who post on here, as well as debt advisors who all come highly recommended. You can visit
www.iva.com for a list of companies, or try Melanie Giles, Size5, Andy Davie or VikiW. Their contact details can be found on the left hand side of the page under the expert link.
I can understand your sons reluctance to accept from you as it is a terrible feeling to be in this position, but I think he is very lucky to have understanding parents like you.