There are many different types of spectricide, but it sounds from your message like he used an herbicide on the lawn. Most herbicides only work on contact with the plant while they are wet – there is no residual effect once the spray has dried. So your garden is probably safe and the damaged plants shouldn’t pass anything on. However, carefully read the label for full information – if the whole bottle was used, you can look at <a href="http://www.spectracide.com/">their website</a> to find and read the product label and look for any cautions about replanting.
I’d avoid eating the damaged tomatoes, though, to be on the safe side.