Passport requirement went into effect at the beginning of 2010. The law passed not long after 9/11, but the feds kept postponing the enforcement date until last year. If your friend from YYZ is going to cross into the US, he will need a passport too.

Windsor train station is not downtown, but a mile or two east. Not sure what transportion options there are from VIA station to downtown Windsor. I assume taxi would be quick and easy. You might check if Casino Windsor runs a shuttle.