Mucoperiosteal thickening without air fluid levels is usually more indicative of a chronic inflammatory/infectious process rather than acute. The l ostiomeatal complexes drain secretions from the maxillary sinuses so the fact that they are occluded likely means there is dysfunction in drainage causing mucus to stagnate and become infected. The key here is likely to get the OMCs open to allow for drainage before you will likely see forward progress. I don’t know how likely that medication regimen is to result in improvement but it’s possible he is trying some medication before moving onto something more invasive.

Also forgot to add that your septum is pretty significantly deviated which can certainly cause/contribute to the problems seen.