The Citadel is under attack by Cerberus forces, during the mission whilst saving the Salarian politician an assassin Kai Leng fights and wounds Thane. After taking back control of the Citadel, Thane is admitted to the hospital.
He has lost a lot of blood & even with his son's help, because his Kepral's syndrome is in it's final stages, his time has come.
The weapons in the game can be upgraded with various mods & by only carrying a few weapons your powers recharge quicker. I only carry the Assault Rifle, Sniper & Handgun with damage & ammo capacity mods equipped.
Time to go find this Kai Leng for some revenge.