Paul talks about believers who have died, who are still alive, and those who will be alive when Christ returns.
This can be stated in positive form. AT: “We want you to be informed” or “We want you to know”
Here “brothers” means fellow Christians.
Here “sleep” is a euphemism for those who are dead. (See: rc://en/ta/man/translate/figs-euphemism)
“because we do not want you grieve like the rest”
“like people who do not have hope.” It can be stated clearly what those people do not have hope about. AT: “like people who do not have the hope of rising from the dead” or “like people who do not have the confident expectation of rising from the dead”
Here “we” refers to Paul and his audience. (See: rc://en/ta/man/translate/figs-inclusive)
“rose to live again”
Here “fallen asleep” is a polite way to refer to having died. (See: rc://en/ta/man/translate/figs-euphemism)
“when the Lord returns”