I want to say again that I think you did was very humanitarian, kind, generous. Your kindness was able to be there in spite of his personality being annoying to you. You considered his family, his child and gave them a possibility of hope. I think it's wonderful.
Your intentions were for your co-worker, and not against your employer.

I am sorry that you have to suffer for this.

A good employer wishes good employees could stay, but trusts their hiring skills to be able to hire another good employee--especially in this economy with so many good people looking for work! High employee turnover should be expected in minimum wage paying jobs. It is part of the nature of the business.