The airbag light came on (solid not blinking) and the dealer said to replace the entire passenger seat because of a bad airbag module.

The airbag in the passenger seat needs to be replaced. You have the option to replace just the airbag or the entire seat. If you choose to replace only the airbag, you’ll need to cut open the seat and then sew it back up. For seat replacements, consider checking car-parts.com.

It's a common misunderstanding that the term "airbag module" can refer to either the airbag itself or the airbag computer. To avoid confusion, it's best to refer to the airbag computer as the "airbag computer" or "airbag control module."