...One unusual thing if he tilts his head toward the ear with the hearing loss this improves his hearing. Would this mean he has fluid in the ear? Any advice?
A high possibility of a partially-filled middle ear. Fluid in the middle ear dulls sound from outside, and increases sound pickup via bone conduction into the middle ear. It can make chewing noticeably louder, and tooth brushing on that side should sound louder too. Does he ever hear any glugging sounds or maybe an occasional high-pitched short squeal from that ear?
These can be from some air momentarily making it through a eustachian tube that has closed up, and opens a little bit for just a moment.
Fluid in the middle ear can take a long time to be absorbed. In some cases, if the fluid is thick, it's possible to have an infection in the fluid (the true "glue ear"), which is not reachable by antibiotics, as the infection does not have a connection to the blood stream. In some cases, a small grommet is inserted into the eardrum, and an antibiotic can be injected into the middle ear via the grommeted hole.
An ENT will look into the ear with a light and magnifier to look at the eardrum, fluid changes it's transparency. Earwax is commonly an impediment to viewing.
Also, a tuning fork can be struck on a desk, and then the patient is asked which is louder... hearing the sound through the air via the resonating fork held next to the ear (using the outer ear and eardrum),
or,
with the base of the fork pressed against the side of the jaw bone or side of head (bone conduction).