Thanks for all the responses.
To clarify: One person would have a drum machine unit and use the preprogrammed patches. There are ususally many, many choices on these units, and he would know which patch went to whichever song we were playing next, dial it in and we'd all start. We wouldn't be programming the machine for each song. They are classic rock cover tunes that have pretty standard drumming in them--nothing tricky, nothing improvised. Ex.: Twist n Shout.
I had thought it would be cool to also have him play some congas and stuff along with. Or maybe it would be better to have he machine do something very minimal, like a bassdrum n cymbol thing and then have him play congas and percussive stuffs. What you think?
This is hypothetical at this point, but could allow for some gigs in local small places.
thanks