He needs something like this:
http://www.trailmate.com/adultTrikes.cfm
They claim these dealers:
AGAR ENTERPRISES, INC. BOX 333, ONANOLE, 204-848-2535 Web Site
ATKINSON SPORTING GOODS, LTD 512 MAIN STREET, SWAN RIVER, 204-734-4760
BELLE RIVER SPORT 481 NOTRE DAME STREET, BELLE RIVER, 519-728-3717
BRAUN'S BICYCLE 27 SCOTT STREET, KITCHENER, 519-579-2453 Web Site
DIXIE LAWN & CYCLE 27 ERIE STREET NORTH, LEMINGTON, 519-326-4572 Web Site
GOOCH'S BICYCLE & HOBBY SHOP 185 SHERBROOK STREET, WINNIPEG, 204-956-6571
VELO ADVENTURES QUAI DES CONVOYEURS, MONTREAL, 514-288-8356
WALK AND ROLL 98 LAKESHORE DRIVE, NORTHBAY, 705-474-5619 Web Site
I don't know where you get this kind of bike, though I see people on such things from time to time. Try a local bike shop, here in ontario you can try:
http://ucycle.com/index.php
They should be able to direct you.
Our local Pickering shop occasionally has these also, it is called Bay Cycle.