You dont ask your mother in law to pick her daughter if the same daughter was not involved in pushing you to the wall.
The writing must have written just before he hang himself.

.....4hrs of commotion!!

Neighbour story is a difficult one. Should you go and check? Should you not go? Will he turn on me? What should I do? And many such dilemmas...

The reality is that quarrels will always be there. Just like in the jungle, dominance, submission, compromise, mistakes etc, and people react differently.

My best advice will be:
1. "Bibi na bwana waki*ombana nyumbani, wacha wenyewe mpaka waelewane"
2. If your wife has done a mistake, talk and try to resolve.
- First between the two of you,
- next close family members,
- next parents
- finally step (3) below...
3. If the dispute is non-reconcilable and you can't forgive her, then take her back to her mother. If she's kichwa ngumu, 'washana' naye, pack your important personal belongings and leave the house for her, make sure you can support the children edu, food, clothing, housing and go start new life!

I do not agree. You should never involve other family members in your manenos they'll always be bias and that would be the beginning of the end of the marriage. Either get a cleric or an independent counselor but always remember that God put in you all the power you'll need to resolve anything if you put ego aside.