Co-sign lease - other roommate wont pay or sign 30-day Roomate

Background:
1 Year Lease (5 months left)
Rent: ~2100/month
50/50 payment

Okay, so my name is Drew and I'm finding myself in a difficult situation. My housemate refuses to pay his portion ($1050) of rent or give 30-day notice of leave. I contacted management and told them the issue, they suggested i sign over a 30-day and they would contact him to persuade him to do the same. He denied it. Last month (December) he could not pay rent and I paid his portion as well under the stipulation that he pays it back over time. He's paid me 300 dollars of total 1300 owed (addition due to late fees). This month (January) he looks to be refusing to pay rent and I am no longer willing to pay his half anymore.

I know this can go either two ways, I pay his rent for the remainder of the 5 months and take him to small claims, I refuse to pay the remainder and this goes to eviction where my credit is effected but again, i can go to small claims to collect the remainder of my 1000 and hope that the judge determines he's the cause of break of lease and pays my fees.

good news is that management is working with me because he's been a late payer for many months now. This is a problem for both management and me since I know my credit is on the line here.

Any advise here?