Is it a temp thing? I really wouldn't just change him to sleeping outside.. cant he be kept in one room over night or something? I really dont think it would be fair and I dont think he would just adjust to it straight away without alot of noise. my dogs go barmy when we leave them out for more than 5 mins.

Would your family be willing to buy a heated kennel or something? or maybe rehoming is the best case after all? I dont think its fair that its suddenly changed like that and I know its not your fault at all but maybe rehoming would be a bit nicer on him? that way he will be able to deal with a change permantly and settle straight away.