The unit says it has an RS232 interface so with the proper card slot connector (or some soldering directly to the pins) you could connect it directly to a computer to control it. From an Arduino you would need a TTL (0V to 5V signals) to RS232 (-12V to 12V signals) converter.
You need the documentation for the unit to know how to "talk" to it (the "DT or OEM / Cavro protocols"). You'd need to get those docs from the manufacturer; it's quite possible that the manufacturer doesn't even release the protocol but rather supplies software that it expects you to use instead.
Beyond that, for the $50 investment it could more than likely be brought back to life if you just ripped out the control board and implemented everything with an Arduino. Looking at the pictures it appears to have two stepper motors which you could interface with directly for control. Stepper drivers for small motors like these would set you back $15/each. There are probably also a few solenoid valves but those again are pretty easy to control.
Hard to say if it's a good buy or not. I'm also unclear as to how having a precision pumping unit alone would help you with titration.