My Father Has Just Had His 4th Heart Attack And

My father has just had his 4th heart attack and we were told he is at 20% heart function. He has CHF and LLC leukemia. He is retaining about 5lbs of fluid as of now, they have prescribed him lasix. The dr basically told us not to bother bringing him back to the ER for fluid retention. Stating nothing can be done for him with his heart being that weak. Is this true???