I know the Asian mentality is to not talk about it but in this case you may have to sit your family down and talk about it and then talk to your hubby and then everyone together. This is all about miscommunication that needs to be addressed. I am going to blunt with this so sorry in advance. Mums do nag but your mum needs to understand that even getting nagged at constantly gets annoying after a while, your father is being tactless and inconsiderate on the low fuel part. Your sister is honestly childish for behaving like that by blocking him and also her son behaving like a brat. When you say 15, I am guessing 15 years? By then you actually aware of things so the fact your hubby kept saying constantly to keep his volume low and he refused means consequences which your sister should understand.
To your hubby, just tell him that your parents are concerned about him but also especially you. So they just want to make sure he looks after himself properly including you especially since you will be busy with your family. Also to apologise to your nephew for lashing our and said he could have handled the situation a little better but also explain why he was angry.
The last is your family, let your mum know that your hubby lived alone and is not use to being told (don't use nag) what to do so instead of telling him all the time, maybe she can just ask him more as a question and not tell him as often. Tell your father that maybe if he uses the car, could he help to top up the gas, or if the car needs repair to ask your hubby the next time he does use it, does he also want him to send for repair as a thanks to your hubby letting him lend the car.
Let your sis cool down and explain what happened to the situation and why your husband got angry and later bring your nephew and both of you explain that although he wanted to hang out with his uncle, he must also understand the bay was sleeping and was told constantly to keep the volume down and ask him to put himself in his uncle shoes. And have your nephew apologist to your hubby and get your sister to apologise as well.
This all should be done if moving out is an issue for you now
Anonymous