This matter has him so worried he hasn't slept well for days.
Tips
memory
牵 (pull) + 心 (heart) + 挂 (hang) + 肠 (intestines): your heart is being yanked and your guts are dangling. Visceral image of constant worry — close cousin of 牵肠挂肚 (qiānchángguàdù), which inverts the order.
usage
Used for ongoing worry about absent loved ones or unresolved situations, not momentary stress. Often paired with 日夜 (rìyè, day and night).