I had a similar experience 6 years ago with CHF. Apparently, with your husband's condition there is heart wall impariment due to ischemia (lack of oxygen) to heart cells, and the left ventricle enlarged causing weak contractions and low cardiac output. Blood backs up into the lungs as the weak heart is not able to pump the blood into circulation. Fluids leak into the lungs causing congestion.
Medication (ACE inhibitor and beta blocker) reduces the heart's workload and a few months later my heart size returned to normal and a normal EF59%.
An echo in 6 months, if no symptoms, would be appropriate to evaluate heart size and pumping efficiency. I have not any medical problems with the medication and feel fine. Every 6 months is the schedule for consultation and blood tests (medication can cause kidney problems). I've had 3 echos, stress test (treadmill), CT scan 128 slice, ekg and a chest X-ray.
I resumed normal activities after 4 days in the hospital normalizing oxygen level, etc. Hope this gives you a perspective, and your doctor is not acting without due care. It requires some time to determine if the medication is effectve.
It is great that he feels better. I know it is hard to wait. I pitched a bit of a fit when my cardiologist office wasn't going to do another echo after my stress test because I had one a month before and they said the ins co most likely wouldn't pay for it. I said but the echo's are under different circumstances and that if it most people get one after the stress test then this should not be different. I won and got the echo and ins paid for it.
When I had my other heart problem years ago, they waited 3 months before the next echo after I started medicine.
Ask them why they wouldn't do it and ask when will the do the next one.
I'm sure others with more experience will give you more information.
Good luck,