Icycle

I have been riding a loaner tandem which has what seems to me to be a weird brake configuration. The right brake controls both the front and rear cantilever rim brakes simultaneously, while the left brake controls the rear drum brake.

Is this a normal brake configuration? What are the pros and cons of this setup? Anything I should be aware of or watch out for? I don't really feel comfortable making major changes to the setup of this tandem, since I'm borrowing it from relatives.

zonatandem

This is an older type setup for brakes and really no longer being advocated.
Some have it setup so one lever controls both drum and rear canti . . . but this is also rather inefficient and robs you of some braking control.
Suggested set-up would be left lever for front canti, right lever for rear canti. A barend shifter can control the rear drum by captain.
Or . . . give stoker control of the rear drum as in all likelyhood it will not be used often except for long steep descents or as a parking brake.