As deadrat says, without more context it's hard to comment clearly.
Nonetheless, your first version sounds wrong in part because it's ambiguous. The first four words are ungrammatical by themselves (concern is a noun and something acting as an adjective is needed — concerned, perhaps). Thus the first four words misdirect the reader to expect a different construction than you go on to deliver.
The focus of your thought in the sentence is he, not they. So you confuse things by starting as you do. I would use the grammar to reinforce the thought by making the same point but beginning the sentence with he.