The iMac DV model that shipped with OS 8.6 had a 400 MHz G3 processor and can support up to OS 10.4.x (Tiger), however to run that version, it would likely need to have more memory installed and (possibly) a larger capacity hard drive. The original 10 or 13 GB drive may not have enough remaining space to install/run OS X. If there are any thrift stores or computer recyclers in your area, an older/used printer may be the solution that avoids the need to upgrade the OS. The Epson 740/740i is about 13 years-old now, but replacement inks for it are still carried by many retailers. It features USB and serial port printing for Macs and USB and parallel port printing for PCs, which still makes it a versatile printer for both platforms. It's compatible with OS 8.6, as well as all supported versions of OS X for that iMac, so your friend could still use it if/when OS X were ever installed.