Hii! If his gall bladder is removed that means that bile cannot be stored to be released in large amounts when needed
Thus he has to reduce his intake of fats because when bile is directly released from liver into duodenum it is only in small amounts so they might not be enough to emulsify all the fats to increase Surface Area to Volume ratio for lipase

For the second part right, they said that he will die from liver failure which means in the ans we need to address all the functions of the liver and how without the liver carrying out these functions we will die
For example, liver stores iron right so when there isn't a liver working, the haemoglobin released, from the breaking down of worn out red blood cells, will not be broke down to produce bile pigments
So this leads to indigestion of fats ( since no emulsification of fats) thus oily stools and the fats are egested from body.
Moreover, there will not be enough fats formation of cell membrane etc thus the stored fats might need to be used up leading to weight loss etc etc

Or u can even say that since liver regulates the the blood glucose conc by storing excess glucose as glycogen, without liver our blood will have a high blood glucose concentration ( leads to diabetes which leads to kidney failure which leads to death as no excretion of subs so toxicity of blood increases, and the water potential of blood also decreases so red blood cells become crenated )