What a trial for you! Sometimes waiting a week or so to let the information settle helps with making a decision like this.

I have no experience with IVIG, but I can comment on Cymbalta.
This drug is very similar to Effexor for pain. It also carries some risk to the liver, so tests should be done periodically while people use it, and alcohol is absolutely contraindicated for it.

The bottom line in any decision like this is :
benefit vs risk.

You might investigate supplements to try and determine if something is missing in your husband's diet and life that is contributing to the neuropathy.
B12 levels? (often become very low in the elderly)
Vit D levels? also critical and when low more pain is the result

Other things that may help are:
acetyl carnitine (for toxin or drug induced PN)
r-lipoic acid
CoQ-10

There is a supplement now for aging and neuro deterioration due to failure of mitochondria in the cells (these are the energy cells). The product is a combo of carnitine/lipoic acid
and their website has some good info on it.
http://juvenon.com/index.html?campai...FQUMDQod3Skt3Q

If you decide not to do the IVIG or even if you do, while you are debating you can read Dr. Ames' site, which is very interesting and helpful.
You don't have to buy his product, and you can choose your own sources for the nutrients. (Juvenon can be more expensive).

Many people feel better on a supplement which can help restore some lost functions. So do consider something along this line. Most doctors will not offer anything beyond the standard RX drug therapies, which today don't do much.