differing views on drug intake

If a patient has chronic Afib and with a low EF of 39%, can he take diltiazem (200mg) and propranolol (10mg x 2) at the same time? This patient is not on self-medication, but the fact that he has seen two doctors, that's the problem.

The first doctor prescribed diltiazem (200mg) and propranolol (10mg x 2), apart from warfarin (2mg), lasix, potassium supplement and a rosuvastatin. And as his condition has not improved, he was forced to get other medical help, and when treated by the second doctor, he was given bisoprolol  to replace the diltiazem and propranolol. The other drugs taken by the patient are still maintained.

It was due to the low EF that the second doctor found it necessary to remove the diltiazem as according to him, both the drugs (calcium channel blocker and beta blocker) work the same way.  But the first doctor does not agree. He says they work differently.

Also the first doctor says that propranolol is better than  bisoprolol as it is given twice a day so it provides better coverage as opposed to bisoprolol.  But many say that bisoprolol is definitely better than propranolol.