Complex sentence: Barrie wished to follow a career as an author, but was dissuaded by his family, who wished him to have a profession such as the ministry, telling him that it was what David would have done, had he been alive.
Split into simpler sentences: Barrie wished to follow a career as an author, but was dissuaded by his family. They wished him to have a profession such as the ministry, telling him that it was what David would have done, had he been alive.