Matt,
One of the drawbacks of a drawknife is the long cutting edge. If the edge gets boogered up it will take a lot to get it back into shape. If you can sharpen yours with a file the blade is too soft to hold an edge.
The old time woodwrights used the drawknife on green wood so sharpness was not so important. Also, it was designed as a roughing tool and it takes some experience to do fine shaving. Don't use it on anything critical unless you know you've got the knack.
If your father has a spokeshave borrow it. It sharpens more easily and can be adjusted for fine or heavy cuts.
I have two old, well sharpened drawknives in my collection but most of my shaving is done with an old bottom of the line Sears/Dunlop spokeshave that I got for 50 cents.
Charlie

: Does anyone here know how I should go about sharpening my father's draw knife
: that he lent me? Should I just use a file along the edge? Or is ther some
: more precise method that I should be doing? Thanks in advance.