Les jours de Mathieu (1968)

A man who is socially inept and out of touch with the world lives with his sister in a small farmhouse. The overly sensitive man lives off his hard-working sibling, taking odd jobs as he gets them to secure his meager earnings. When he brings home a woodcutter from the forest, the sister and the newcomer fall in love. Terrified over a life without his sister, the man can't cope.