Tricky question. Andrew Lang wrote Aribian nights in 1855, however the story originated from aribic in 1706... And the merchant and the genie was a story about Abou Hassan, first written in English by, John Payne.
I would say the correct answer would be Alex is his brother since the way the statement is worded, first it talks of his sister, then of his brother Jerry and next his sibling, Alex so since it comes right after the mention of his brother Jerry I would think Alex would be a brother though I can't prove it .
Another word for accelerate is increase speed
