Im sure if your going to put a highspeed internet in Cebu just for video call to be able to stream video back home, then downstream is important. unless you want your parents to stream a high quality video stream from them as well, so they need a higher upstream as well. I think 1Mbps (that if your not going to stream high definition video) down/ 256kbps up is fine, but the higher you will subscribe the better.
But if your gonna need to have a descent video from your parents, depends on the quality of video you want to stream from them. The higher the quality, the higher speed you need to stream with ease. Im not an expert on this, im sure somebody who has more expertise on this could solve your problem in here. But if your just going to use Skype, i think they will only need to have 512/128 dsl line.