Universal Truth,

It is a rather long read, but worth it - not only because it is one of the best russian books of the 19th century, but because it describes your husband. the book is called "Dead souls", by N. Gogol, available from Amazon, and the character (one of many) who is like your husband in that he has all those plans but never executes on them is Manilov. In Russian there is even a noun, "manilovshina", meaning manilov-kind-character, that describes exactly that type. Please read it - it will be eye-opening for you.

Re: the little sister. I think the only solution is to have him invite her over, in an email, copying you. Otherwise you do not know what is going on. Just a nice polite invitation to dinner or something, with a note that you would like to meet her.