Wow... that sucks...
Well if it were me in this situation I would consider two options. Not sure if they would help but who knows.
1. I would try
http://www.spamarrest.com/. When someone sends you an email, they are sent back an email back asking them to confirm that they sent the email to you in the firstplace. When they click the link it asks them to type the word. However I think they give the option to listen to the letters if you cant read them.
2. Setup your own confirmation script. It sends them an email asking that they confirm the submission and if they click the link the email will be sent.
Unfortunately they are spamming him through a form which means that they are specifically spamming him, not just sending to a massive list.
Another thought is, if his/her website has a member login section, possibly he/she can set it so they can only contact him/her via that form if they signup? Just a thought...
Hope that helps
