My question involves landlord-tenant law in the State of: Illinois

I entered into a lease with a roommate in June wherein we each payed 1/2 of the security deposit. The roommate had a dog (I did not) but the land lord did not charge him a pet deposit since our security deposit was the amount it would cost to replace the carpet. While we were living there I was offered a job with a substantial raise that would force me to relocate, I accepted the job. The roommate and I came to a verbal agreement that I would move out the first week of October and continue to pay my 1/2 of rent until Jan 1, at which point he would take over the full rent. The landlord was made aware of the agreement. Or lease expired the proceeding June when the remaining roommate moved out. The landlord did an inspection and decided the carpets needed to be replaced because of multiple dog urine stains. The landlord provided a statement where it was stated we would lose the deposit because the carpets had to be replaced because of dog urine stains and a heavy dog odor.

Do I have the ability to take the land lord's pictures, statement and bill to court and sue the roommate for my half of the security deposit?
Can the roommate counter sue for rent that I didn't pay even though we had a verbal agreement and the land lord was made aware of the agreement?