Hello it is nice that it looks like you are attempting to make a new boss, but it doesn't look like you are doing it properly.
It looks like you got a random model online that hasn't been made to work with TF2. The models file doesn't look like its compiled as it has a bunch of files that shouldn't be there when its compiled. And it has no material files.
You can't just use a random SFM or GMOD model without extra work, the model needs to be "rigged" to an existing class.
Unfortunately I cannot teach you how to do this as I don't know how to do this myself. All I know is that it needs to be done. If it was as easy as downloading a random model online, we'd have custom bosses.