Excessive hair loss and ltos of scratching and bititng?

Question
'My aussie is turing two in 2 weeks and for the past 3 months he ahs been scratching and biting and his hair has been falling out in a very rapid pace and i thought it was fleas so i bought him his flea shampoo and his normal shampoo and gave him two baths, an di thought it was working but it started up again and i tried only the oatmeal shampoo and it worked for like 2 hours and now im desperate because i have another dog she is a pitbull and when she was a puppy she had mange and she was treated but the doctor said to be careful and he said that mange isnt contagious to other dogs now im not too sure and a friend told me about Neem oil and Leaves but i dont now if whether it actually works, please help and to give a bit more info
I cant afford to take him to the vet because my parents think this can be solved at home?

Answer
If you think the dog has fleas, part some of his hair and look for "flea dirt" (also look to see if there are any sores or hot spots)- flea dirt looks like little black flecks (they are actually the flea poops).  When you bathe the dog have him sit in the tub for ten minutes soaped up - that kills the fleas - then bathe him again the same way ten days later. Flea dirt will turn red in the water, because it's mainly blood.  NEVER use more than one flea product at the same time on a dog!!!  Vets usually prescribe benadryl for itching - the pink tablets that you can buy over the counter - but I don't like to inappropriately medicate a dog.  Spending a bit of money up front is a good investment to keep the dog from suffering.  Failure to treat a dog is actually a crime now in some states and is considered animal cruelty.  If you cannot afford care for your dog, it's unfair to have him suffer like that.  You can surrender him to Aussie rescue and have him find a home with someone who can afford his care if it comes to that.
Your Pit probably had demodectic mange, which is not transmissable.  The contagious kind is sarcoptic mange.  If your dog runs loose where foxes and coyotes are found, not only is he in grave danger from being killed by a coyote, he can be exposed to mange.
Hair loss can also be associated with hypothyroidism, common in Aussies, but easily treatable with an inexpensive medication.  My dog has it, and I pay $90 every six months to have her blood tests, and about $17 a month for her prescription.  If left untreated, very serious consequences may occur, but a dog that is cared for properly can live a normal lifespan and do everything that other dogs can do.  I hope your parents reconsider and let you get the dog diagnosed, because there is something radically wrong with any dog who is tormenting itself with biting and scratching and has hair falling out.