I am very sure that guy was indeed Dr Etienne Grech because i skyped with him before and i remember very well how he looked like on skype
That is usually what a scammer does to convince you he is real: use an old footage of the person he pretends to be during a Skype call. The image will freeze on the screen and the sound quality will be bad. The call will not go on longer than few seconds.
The scammer can have a better solution for a longer screen presence during a Skype call. There is a specific software that can be used for that, based on a picture of that person. The software is accessible and can be downloaded for free in certain forums and it will allow a basic interaction - meaning the person on the screen will move, wave or even blow a kiss. He will not have sound (any excuse will be good for that, like a microphone not working or him pretending to be in a place where his voice can disturb others).
Anything online can be faked if you know how to do it. You were not in contact with the real Dr Etienne Grech.