Disklavier

Why not try a sideways solution..
 
Your goal is to hear your mother playing on your disklavier.
 
Why not arrange string parts, bass, etc and play her complete audio as is,  
along with your arrangement on the disklavier.
 
It would be sort of like Natalie Cole recording with her dad. Using some  
old, some new, and creating a new work  that has the old   there  too.
 
;-)  

Blessings,

Wanda