Manda d-hayyi is a phrase in Lebanese Arabic that means "whoever is alive." It is used to show gratitude and appreciation for those who are currently living.
Think about it like this: When you're happy or excited about something, you might say "Yay, I'm so glad I have my friends and family with me!" Manda d-hayyi is like a way of saying that in Lebanese Arabic.
It's important to appreciate and cherish those who are still with us and to never take them for granted. Manda d-hayyi is a way of reminding ourselves to be grateful for the people in our lives who make it better.