This is rather important in terms of business, either he does it properly or he doesn't have one at all, as a cack handed put me together site will do much more harm than good. It will give out all the wrong messages to prospective customers.

Why doesn't your cousin ask your brother to do him a WordPress theme?

Yeah, I completely agree.

The site got to a point that looked fairly professional. Since then he has added gadgets and gizmos and widgets and scrolling ticker text and it doesn't look anywhere near as good.

He won't listen though. He always wants more.

If he won't listen then there comes a point where you need to wash your hands of the whole thing…

That's been and gone

From a dude off the street point of view (i.e. no website development knowledge) I think it looks good and was interesting to read imo (apart from obvious errors that have already been pointed out).