What specialmom says is certainly correct.
It is also important to learn how to deal with a child with ADHD. Its very different than working with a child without that doctors diagnosis. And I can guarantee you that spanking will not solve any of the problems and will in fact only make it worse.
I am also the CL on the ADHD forum -
http://www.medhelp.org/forums/ADD---ADHD/show/175 and have a lot of resources available that can help you if you have the need. I would highly suggest that you buy the book - "The ADD/ ADHD Answer book," by Susan Ashley. Its about 10 bucks on Amazon. It has a ton of stuff that can help.
Also, check out this site - http://www.help4adhd.org/en/about/what/WWK1 - it has a ton of good info on ADHD which you need to know about and I think will find helpful to share with your husband.
By the way his attitude reminds me a lot of other adults I have seen who themselves had ADHD and toughed it out. Anyway, its a good chance that someone in your family has it because of the strong genetic link.
Hope some of these help! And feel free to post over on the ADHD site if you need more info.