Nope. You have to leave the country and apply for another visa at the Consular Officer abroad.
Yes you can extend your visa
You need a visa expension tourist visa form.
Yes, Indian tourist visa can be extended on medical grounds.
If you have a non-immigrant visa and want to extend your status, you need to file form I-539, Application to Extend/Change Nonimmigrant Status. K3/4 and V visa holders too may file this form to extend their stay while they wait for their petitions to be approved. This form is filed by F and M visa holders to have their status reinstated. It is recommened that the application be filed at least 45 days before the expiration of the stay. The date can be found on the I-94 card that is stapled to your passport at the Port of Entry when you enter US.
In a word--no! http://www.dixonimmigration.com/index.php?pid=2
A visa is intended for visiting relatives and touring the United States. The visa that was issued was not intended for medical reasons, for reasons of medical issues; not including pregnancy, there is a special visa that can be obtained.
You have to extend your visa each time if you choose to stay longer
There are essentially two visas for Filipinos traveling to Australia. One is a tourist visa for less than a three month stay. The other is a business class visa that can be used to extend a visit for business or school.
Yes, there is nothing on the USCIS site that mentions that you can only extend one time.
You are unable to extend your J-1 Au Pair Visa. If decide to participate in an au pair extension program (6, 9 or 12 months) you are able to return to your home country to obtain a NEW J-1 au pair visa. This application needs to be done before your first year visa has expired. While it is possible to apply for a new J-1 Visa back in your home country, there is no guarantee that the visa will be granted. If your second visa is denied, you will not be able to return to the USA.
In order to visit Australia one must purchase a visitors visa. The charge for a visitors visa is AUD70. It is possible for one to extend their stay in Australia up to 12 months.
30 to 90 days depending on your VISA some countries extend to 180 days.
They usually do not extend the visa a second time unless there is a very good reason. You would have to leave the country or get a student visa and see if they'll give you that but of course you would need to study something.