The idea of the dying grandmother leaving behind a trail of letters leading her outsider grandchild on to a series of significant people indeed owes quite a lot to Jonathan Safran Foer's brilliant 'Extremely Loud And Incredibly Close', especially as the grandchild in question has a large number of character traits in common with Foer's Oskar Schell.
But OK - There are worse references to pick from!
Backman does have a style of his own; there is nothing elegant nor poetic about it, but it is entertaining and idiosyncratic enough, all in understatement (let's be literary and call it litote).
Funny at times, though in order to reach perfection, or even maturity, his style lacks the same thing as his plot : Moderation.
There is just way too much of everything in this book, including pages.