People who can’t hear well often rely on other senses more heavily. You can try flipping the light switch to alert him. Also he may be able to hear frequencies lower than your voice better. A light foot stomp may work. He is likely to be aware of vibrations and moving air too. That could come from a swinging door pushing air toward him or walking heavily on a wooden floor.

Just be aware that as we age we become more focused and less tolerant of distractions and that is independent of your husband’s hearing loss.