"next to whom" is a correct and usable phrase in written English.
It is typically used to refer to someone who is physically or figuratively beside another person. Example: The shy girl sat next to whom she thought was the most popular girl in class.
Her aim was to chart who sat next to whom at lunch.
No wonder that Welsh invents the terrifying Begbie, a character next to whom all others seem hampered by scruples.
To her neighbors and co-workers, next to whom she is comparatively privileged, she often seems haughty, selfish and capricious.
They had already been feuding for weeks about such trivialities as who would stand where in receiving lines, and who would sit next to whom at banquet tables.
Usually, this would have been the end, but the video now continued with interviews with the young martyr's parents, next to whom I was now standing.
A lot of the impetus towards financial reform and oversight have been replaced with the "who's sitting in the lunchroom next to whom" analysis of politics.
Davis looked lithe Sunday, certainly next to Anthony, whom he found himself guarding at one point.
The man in the bed next to him, whom Stewart believed to be drunk and homeless, picked up the box.
It's surely more fun to fly next to someone whom you are interested in than it is to share a row with a bore.
Aaron Copland, Milton Babbitt, Arthur Berger and others were there, and I found myself sitting next to Elliott, whom I had never met but whose Piano Sonata I was then working on.
Stack, of Long Beach, who was invited to compete without having to qualify, seemed nothing less than thrilled to be surfing next to Slater, whom he calls "the sickest guy ever to surf with".
