Active job

Subdivision feasibility -Help!!!!

My father owns a house in Avondale I think the land is about 678 Metres squared. We (my husband, kids, brother and sister in law) are all cramped up in his house and I would love to put a house on the back of his property but he is saying it's too expensive, you can't subdivide and that he will tell me when the best time is to build/subdivide. He is an architect and part of me wants to believe him but part of me is thinking he is just making up excuses! I need someone to help me find out if Subdivision is feasible and to tell me how much it will cost! Our property is runned down and the drive way is a disaster! HELP!!!!