Complex sentence: Having been smothered by his mother for most of his life, he has had a sheltered upbringing, and is often naive to the dangers of the world, and his interactions with other people are generally awkward, particularly around people his own age.
Split into simpler sentences: Having been smothered by his mother for most of his life, he has had a sheltered upbringing and is often naive to the dangers of the world. His interactions with other people are generally awkward, particularly around people his own age.