It's definitely better done by porting it to DECB (Disk Basic) which shouldn't be too hard for someone who knows the platform properly. I was just presenting a pointer for the moment.  fweeplet is derived from fweep so it's C and portable which is always handy. DECB is alas not my area of expertise so it would nee dsomeone who can replace the I/O routines and disk open/close/read/write stuff.

Fweeplet under Fuzix on a COCO can run Z5. You probably want to recompile it with -DMACHINE_BIG for a COCO3, and a native port that used DECB and the extra RAM not disk for paging would run far better. So it's currently possible but a bit hacky and you need SD card or similar.