Remedy for teenage boy suffering from persistent cold allergies, PND

Looking for some advise on line of homeopathic treatment for my teenage (14yo) son, who has this almost persistent cold, throat irritation, allergy symptoms, waves up everyday with blocked nose + sinuses, post-nasal drip, irritation in back-of-throat and top-of-mouth (with the urge to itch those places). He catches cold easily, and the cold lingers far too long. Just as he begins to improve he may get another spell.

He is otherwise a sensitive kid, very observant kid, but also prone to lot of 'lost-in-his-own-world' (day-dreaming) spells, not at all aggressive, but getting to be a little stubborn (not yet too much, I suppose). He is also afraid of few things -- ghosts, darkness and refuses to sleep alone. He is also very imaginative (perhaps reason why some of those fears linger), i.e. after watching some scary movies (like the ones that show some posessed dolls attacking family), he refuses to go into a room where all of his sister's dolls are kept. In general, he is also quite lazy, and while he loves watching sports, reading about sports (and science), he doesn't love doing physical activity as much (and as a result is putting on a little weight as well).

ENT has told that he has a slightly bent septum, and that he might have adenoids -- but we didn't get the nasal endoscopy done.

Had recently started him on a course of Hydrastic 30, thrice a day (today is third day), which seems to have improved his situation somewhat, but I am looking for long term treatment to help him overcome his cold allergy, PND.

Someone had recommended Mimulus Bach Flower remedy for his fears, but we have not started on it yet, though plan to once he gets some relief from his allergies/cold.