@shabia1 - Finally got around to seeing the episode. So I had a slightly different reaction than others -- I was a bit affronted that Imlie started cleaning the room. I think unless you have faced grief and loss of family members in your own home, you will realize that the process for moving on (including cleaning up and sorting out stuff) happens in different ways for different people.
What struck me was this was a room where time stood still and the pillows are on the floor, sheets are as they are -- in my region, the first thing that happens after a funeral is the entire house is swept, wiped clean, sheets, curtains and cushion covers are all removed and put for wash. It is both scientific as well as ritual. The initial cleaning will be usually done by someone close or a well-known servant/staff after the famliy has left the house for the funeral. The cleaning isn't done by the family usually. Here, the linens are there as they are. It is like the family or staff didn't even have the opportunity to clean because there was so much chaos at the time.
Now after cleaning, the next process (after a few days) is the paperwork stuff. Some people are so organized that you don't have to search but for other people, you have to go through desks, drawers in order to find documents. There is life insurance, changing of bank accounts, investments etc. So many little details. That can be very confronting for many and it is not easy at all -- however, because practical details such as transferring bank accounts need to be done for ease, people cannot avoid these.
After that are the personal effects -- now in some families, they will split the favourite clothes and jewels for example among the daughters or daughter-in-laws. Things like that -- however, this can be an explosive time where so many arguments can occur. People are in the process of grieving and are not necessarily rational. Comments can be said which can turn into arguments.
Even if you are not splitting the personal effects, you have to figure out what to do with them. Are you going to donate to an ashram for example? Now, different families will have different timelines for figuring out what to do with the personal effects. There is no ritual that we have to figure this out by xx date. This means that some families choose to deal with the personal effects quickly as a matter of moving on while some families put it off for considerable lengths of time (including years) because they don't have the emotional strength to do it. Regardless, it is up to the family to decide when and it can't be imposed by another person.
In this case, Imlie unwittingly was forcing Aryan to confront his grief -- cleaning up the room should have been his decision and not hers. While it was just dust in her eyes, for him it was so much more. There were feelings there. Some people get mad even if you touch their stuff without asking as it feels like a violation of space. How much more you would feel when there is feeling attached to the room -- he wasn't ready yet but he is being forced by Imlie to look at his grief in the eye. Hence, the anger. The scene and preview reflects the anger of grief, the frustation of grief, the pain of grief.