How do you know this is "my brother is a tired accountant" vs "my accountant brother is tired" (like if you have 2 brothers, one is an accountant and one is a flight attendant, and you are telling your new partner what to expect at the meet-the-family dinner tonight ... vs the given correct answer, which seems more like "I have one brother and, as accountants go, he tends to be the tired type")
You are totally right, and the issue is all readings are pronounced in formal Arabic and then they argue about using spoken Arabic. Spoken Arabic you can't use it to learn as words meanings could be different from country and another. I can't understand why they are not using the formal Arabic where you can use it anywhere in the Arabic countries.
Sure there is a big difference as "Tired" in Arabic means "تعبان متعب" = "Physically he can't handle more work or job and needs to have a break to relax" on the other hand "Frustrated" in Arabic means "مُحْبَطْ" = "Depressed / Sad" which means psychologically tired not physically.