Clutch not disengaging on 03 CTS

Ok, I'm having the exact same issue and it's also a 2003 3.2 only now the car won't even start. Something started going wrong with clutch after my ex did a half ass oil change. Then clutch stopped going into gear to the point I had to turn car off then put in 2nd just to get it home. Now it's like the clutch is just a random piece of metal that serves no purpose. After checking fluids I was shocked the tran oil was none dry and again almost empty about 2 weeks later too. Now a mobile mechanic who looked at it told me point blank it was sabotage because the fluid in tran and brake is WATER ! Also apparently my ex forgot to bleed anything. Is there even a chance that all this trouble could really be simply needing a bleeding?
Thank you

Thank you for your quick reply and your hospitality in welcoming me to the group. Your completely logical and normal answer only reaffirms my need to get rid of some people in my life because I know it is not a faulty design by Cadillac rather a very faulty design in a bf lol. Granted there was a small problem with the shifting when I got the car but water in 2 fluid containers isn't a mistake. Especially when he is very mechanically inclined yet couldn't finish a simple oil change AND didn't notice one totally empty reserve plus 2 others filled with water.
I got rid of bf and am grateful I didn't have my dream CAR the V! Hopefully it won't cost too much to fix.
Thank you so much for quick response and for welcoming me to the group. Truth be told I'm kind of giddy about being in a group with so many V owners, lol.
Thanks again!