Poor little things. Well, the other one is your responsibility now and you got to try to keep it indoors in these hot months. Keep plenty of water, carrots and green veggies around.
Sorry about it but you also have to be sure his place is clean, and it would be good that YOU and not your servants clean at least once a day all the little poop balls from wherever you decide to leave him. Rabbits need at least 4 X4 square metres.
Saying all these, I don´t see the point of having a rabbit!! they do not even make good pets.
Good luck....