Without any doubt, Facetime is a popular video calling app out there but it is designed for Apple devices only. So the short answer is: there is no way to download and install Facetime on Android.
However, it is important to note here that Facetime is not the only video calling app. There are more than a few dozens of video calling apps that work similar to Facetime and are fullycompatible with both Android and iOS devices so you can stay connected with your loved ones regardless of the device being used.
Some of the most popular and the best video calling app includes WhatsApp, imo, Google Duo, Facebook Messenger. Here is the full list of best Facetime alternative apps for video calling on Android.