is/are

As one written sentence it should be "are". But this would be acceptable to say:

How is Bob? And his cats?

PS When you ask these questions can you tag them "english" to make them easier to find for the ESL teachers?

Thanks, Robert.

I will do so from the next post.

As an example of speech, I'd say that "How's" would be the more common usage. And yes, it's fine for speech. It's the same as with 'there' which, in speech, most commonly takes a singular verb even with a following plural noun phrase.

This also works with 'where' and 'here';

Where's my keys?

Here's your keys.