Cocktails before dinner Chez Jacqueline 73 Macdougal
How far can he walk? Can he do stairs?
Little Branch is about 4 1/2 blocks away but down a flight of stairs (they open at 7). Pegu Club is 3 1/2 blocks away but up a flight of stairs (they open at 5).
You might be able to squeeze into the bar area at Minetta Tavern, which is very close by. The cocktails there are excellent. Everything is on the ground floor/street level.
Otherwise you might want to look into Daddy-O or Blue Ribbon's wine bar, Blue Ribbon Downing Street Bar. Both are street level/ground floor.
There's also Bar Henry but that's down a flight of stairs.
Blue Ribbon Downing Street Bar
34 Downing St, New York, NY 10014
113 MacDougal St, New York, NY 10012
44 Bedford St, New York, NY 10014
22 Seventh Ave South, New York, NY 10014
77 W Houston St, New York, NY 10012
90 W Houston St, New York, NY 10012