Absentee landlord won't make repairs, international certified mail?

I'm currently renting a house in Dallas, TX and my landlord lives in Poland (he rented the house out due to his job relocation). We have a nasty mold problem due to a leak in the roof. I am pregnant and fear that the mold is affecting my health. We notified him of the problem and he said he would fix the roof and then the mold, but that's the last we've heard. So, Texas law states that before you have the right to terminate your lease, you have to send your landlord certified mail stating the problem. But you can't send certified mail internationally. We only communicate with him via email. Does anyone have any advice on how to move forward?