Thanks SnSpring, PAri4u, sibnadian and Spons!
I have one more update: I just called CIC and the agent was so helpful. She informed me that they have mailed another letter to me on April 30, 2012 stating that I have been approved as a sponsor and that my file has been forwarded to the local visa office (Nairobi). Waiting for the letter now. I am not sure what the processing time is in Nairobi but I also submitted the PCC for my parents together with the application in Feb 2012. So I guess what's remaining is medicals and payment of fees.
gaggidhillon and Spons, no e-cas status change for me though.