Proverb/phrase for using a tool/process not intended for its purpose
Solution 1:
By using a wrong tool/process to achieve something that this tool/process is not intended for, your colleague, in a way, is trying to fit a square peg into a round hole.
TFD(idioms):
square peg in a round hole (Also, round peg in a square hole)
Fig. someone who is uncomfortable or who does not belong in a particular situation. (Also the cliché: trying to fit a square peg into a round hole, trying to combine two things that do not belong or fit together.)McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
Wiktionary:
square peg in a round hole (plural square pegs in round holes)
(idiomatic) Something or someone that does not fit well or at all; something that will not succeed as attempted, except possibly with much force and effort, or alteration of either the peg or the hole or both beyond recognition.