1. No official bank balance requirement exists for B1 B2 visa sponsorship
Normally, there is no official guideline on exact amount of dollars. But, generally, it is good idea to consider 500 USD for each person you sponsor per month.
In your case, this should be about 2000 USD per month.
2. Can family in India sponsor themselves for B1/B2 visa?
Your brother can sponsor himself. In-fact, anyone who wants to travel to US can sponsor themselves. The procedure to apply is same as mentioned above except that sponsor’s documents are NOT required.
There is no method that can be pointed as better. It all depends on the person’s credibility, judged by Visa officer in US embassy interview.
3. Is B1 and B2 two different visa or same?
B1 and B2 is same visa. I mean the same visa will show that you can either enter on B1 or B2. If his company applies for his B1 visa, he is automatically eligible to enter US on B2 visa too. There is no separate visa issued for B2.
When he enters US, the visa officer will stamp his status as either B1 or B2 based on what he says as his ‘purpose to enter US’.
B1 = Official Business travel
B2 = Leisure travel
All US visas issued remain valid simultaneously. The status in US depends on what visa you use while entering at port of entry and what you say to Visa officer.
As an example, You can have both H1B and B1/B2 visa stamped in your passport and can use anyone to enter US based on what you want to do while in US.
4. Get US Driving License on B1 B2 Visa?
B1/B2 is strictly a visitor visa. Driving license rules are governed by each state and each one has their own law.
In 99% of the cases, you are not allowed to get driving license on visitor visa as the maximum stay on B1 is normally just 6 weeks to 12 weeks.
On B2, they generally just give i94 for 180 days.
And to get Driving License, you need US address proofs which a visitor will probably not have.
An international driving license is recommended but it again depends on state specific law. Many states allow driving on international license (not strictly international though) for up-to 90 days to 180 days.
But, it varies a lot. So, it is better to check with the state he is going to drive in to check specific rules.
I have seen people driving on Delhi, India’s license too as rental car companies do not verify the license (if it is local Indian state or international license).
REMEMBER: Your brother should be INSURED if he wants to drive your car.
In case of rental company, he can buy insurance easily with any license