Dolby atmos speakers for 2 channel

Hi all,

Here's a weird one.  My functional-equivalent-of-a-father-in-law -- a real eccentric -- decided he wanted to resurrect his old 2 channel system --70s Marantz separates, Marantz 6300 TT.  He bought himself some new Dolby Atmos Klipsch towers, not realizing that they were designed for use with special processing technology.  They can be set up conventionally for stereo, but this takes the upward firing speakers out of the signal path entirely.  They are supposed to receive a different input from a Dolby Atmos amplifier.  He is disappointed, and thinks there must be a way to use the upward firing speakers. 

Is there?  The preamp has switches and output for A and B speakers, but I only see one set of speaker taps on the back of his old Marantz amp.  And even if I could run the top speakers as B speakers, and select A&B on the preamp, the top speakers would get full range signal, and the impedances would be wonky etc..  So it sounds like a hard "no" to me.

Any clever solutions?

He can't return them and exchange for proper stereo speakers since he destroyed the boxes on arrival.

Richard