the meanings of expressions using "loved", such as "her loved brother" and "loved ones"
I've just come across some expressions using the word "loved", such as "her loved brother" and "loved ones". I'm wondering whom the brother or the ones are loved by. Does it depend on the contexts? Here are some example sentences and my interpretations.

1. Her loved brother was killed in an accident.
the brother loved by her
2. Relatives need time to grieve over loved ones.
the ones loved by the relatives
3. He had become a well-loved member of staff.
He became loved by the people around him, such as the other staff members and, maybe, his clients.

Question

the meanings of expressions using "loved", such as "her loved brother" and "loved ones"
I've just come across some expressions using the word "loved", such as "her loved brother" and "loved ones". I'm wondering whom the brother or the ones are loved by. Does it depend on the contexts? Here are some example sentences and my interpretations.

1. Her loved brother was killed in an accident.
the brother loved by her
2. Relatives need time to grieve over loved ones.
the ones loved by the relatives
3. He had become a well-loved member of staff.
He became loved by the people around him, such as the other staff members and, maybe, his clients.

Answer

We would not say "her loved brother". That is wrong.
We would say "her beloved brother". 
"Beloved" is the adjective. "Loved" is a past participle that functions as a pseudo adjective when used in the passive voice. 
In your first sentence, "beloved brother" = adjective + noun. "loved by her" = passive voice of verb. They are not the same thing.

1. Her beloved brother was killed in an accident [the brother loved by her was killed in an accident]
2. Relatives need time to grieve over loved ones [the ones who are loved by the bereaved relatives]
3. We are not told who the people are who love him. We can only guess. Your guess sounds correct.

Answer

In this case, "loved" is just a standard use of the past participle to indicate that the noun is the OBJECT of the verb. As with the passive, only context can determine who the SUBJECT of the verb is:

I found a stolen purse (we don't know or really care at this point who stole the purse)

steal: infiinitive
stole: past tense
stolen: past participle
stealing: present participle

Note: My breaking hearting.... the heart is the SUBJECT of the verb

لا تفوّت فرصة تعلّم لغة جديدة وأنت مرتاح في منزلك. تصفّح مجموعتنا المختارة من مدرّسي اللغات ذوي الخبرة وسجّل في درسك الأول الآن!