The inciting incident isn’t entirely clear, as the proxy was he inadvertently responsible for the murder? Or was he framed for a murder he had nothing to do with?

The MC description doesn’t need loving this is implied by defining him as a family man. The dark past description needs to be more specific to clarify the stakes of revealing what he was before becoming a law abiding family man. Also his dark past presumably as a spy, black ops operative or a hit man isn’t relevant to the logline this could be used to flesh out the idea in the synopsis or treatment. You could though maybe allude to his background in the logline.

Better to simplify the logline by having someone frame him to make him need to prove his innocence.
If he is being framed for something he didn’t do Perhaps start with that:

After a family man is framed for the murder of a diplomat by his former special forces commander he must go on the run to prove his innocence.

Hope this helps.

In this logline the personal connection is clear; mother – son. Therefor there is no need for “Driven to the brink of breakdown…” in the logline.

Better to start with the inciting incident as its impact on the MC needs no explanation.

Further letting go is a vague goal as it could manifest itself differently in each person, more so learning it as an art form. Better to specify an action that will be a clear cut acceptance of the son’s death doesn’t kill herself, stops drinking or doing drugs.

Lastly “…guilt and grief destroy them both.” is a vague stake because we can’t imagine a specific visual in our minds of what that means. We don’t know if destroy refers to each of them as people or to their relationship as mother and son.
Do they become depressed? Do they both want to commit suicide? Will they argue and never speak again?

Hope this helps.