Most of the restaurants in malls are wheelchair accessible. However if you want to know about cafes then you can check out The Potbelly (Chanakyapuri), Jugmug Thela, Q Bistro, United Coffee House and The Burger Club.
U can go to IHC , CYBER HUB , And all Delhi haats are universal designs .. Ur friend would b v happy to get something different
Golden Dragon - nearby Ansal Plaza- South Delhi
Excuse Me Boss, Laziz Affaire, AMPM Cafe and Bar, Sports Diner
All American diner and cafe lota both are wheelchair accessible. And many shipping malls in general are also wheelchair accessible.