Assisting one's brother with zakaat money

Q: My younger brother is jobless and has a wife and baby. I gave him money from my Zakaat so he can go to the Middle East to find work. It's been few months and he is still looking for a job and meeting his needs there by using zakaat money which I gave him. His wife is in her home country and needs some kind of financial support to meet her and the baby's needs. His wife has jewellery which is worth more than US$5,000. My question is that since my brother has no income to support her and his wife is a house wife, can I give Zakaat money to his wife so she can fulfill her needs along with baby's?

Following a mazhab

Q:

1. Is it necessary to follow anyone amongst 4 imams? Is there any ahadith? What was their ijthihad towards giving opinions on ahadith? Did four imams mention that "in case what they were doing is later found to be not correct then we should ignore them".

2. Why some Muslims believe that only two shahih hadiths are only hadith and rest hadith like Abu Dawood, ibn Maja, an nasai and tirmidhi are not correct hadith

3. Should every Muslim believe in all ahadith?

Using leather products

Q: I have a watch which has a genuine leather strap. My question is whether it is permissible to wear such watches because we are not aware of whether the animal used for the leather is halaal and has been slaughtered in the halaal way.