This does not make sense -- 回复：留不良纪录对找工作有影响

他预付的定金可能也要不回来。 -- Possible.

Still, this does not make it right to ask parents selling their own house to help the child buying a house. Not to mention: the parents lost the potential appreciation of the house; risk not be able to get the money back; take long time to sell parents' house in China for a reasonable price and wire the money to Australia... Actually, just for the last par, it makes me feel the kids are cheating the parents.

Just tell the kids that impossible to sell the house quickly.