hi guys, i would like to ask about Hepatitis B issue.

So few days ago, my bro went to medical checkup and doctor told him that he have totally zero 0 antibodies of Hepatitis B in himself.

so he going to get the vaccination done.

I not sure whether i have this vaccination during my younger ages 

Is that can straight away go for the Hepatitis B vaccination along with my bro or better to have blood test first?

What is the causes of Hepatitis B? Failure of treatment lead to? i saw people always relate this disease to seafood, dirty water intake 

thanks