An user of my software wants his application runs without mouse

It's a software for a parking lot and he says it's dificult for him to use a mouse there
I have about 100 users of this software and no one is complaining
It's a cheap software

I started to adapt the software the work also by keyboarb, butt as it has
lots of buttons I am considering quit this user rather than finished the adaptation

What do you guys think ?

Is it wise to have mouseless compatible sofware ?
( I dont like to enable tabs )