If messages to your husband go to his spam folder then he (or his ISP) has a particularly stringent set of spam filtering rules in place. He needs to white-list those addresses. He has to do this within his email program. It is not a Nabble issue.
The addresses you quote represent his personal addresses for the different areas of your forum. There will, therefore, be a limited number of them (and in any case you should be able to set up a spam filter rule that allows through any address that ends "@n4.nabble.com". That should provide adequate security for him/you).
The addresses are generated that way by Nabble as a spam protection measure. Only your husband can use them as they will only be delivered to your forum if he is the sender and the address matches the address he used when he registered on the forum. It prevents him from being able to pass on the addresses to other people so evil folk cannot spam your forum.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.