Impurities on clothing and furniture

Sitting on a sofa which was messed with urine

Q: My wife is suffering from a serious disorder about purity. This is all due to urine.

If a child has urinated on a sofa and if someone sits there after its dried without being cleaned, will the other person be impure? Does he/she have to change their clothes?

If he/she sits somewhere else with those same clothes, would that place also be impure?

My wofe is really not well because of this and she’s always washing things, beds, clothes. etc. 

Sprinkling water over impurity to purify it

Q: In my pregnancy I've been getting clear or yellow discharge very rugularly.

So sometimes if I'm out and I have slightly more than a Dirham size then I just sprinkle water over it and try to scrape it a bit but it's always wet, not dry. So sometimes I can't wash and change my underwear when I'm out.

Does sprinkling water over suffice?

It worries me because of my wudhu and salaah and it's validity.

Removing impurity from a touch screen phone

Q: I have a question regarding impurity and touch screen phones. I would like to know how invisible impurity such as urine traces or other invisible impurity may be removed from a cellphone as it cannot be washed as it would be ruined. Would wiping the dry invisible impurity with a dry cloth remove it from the smooth surface of a phone? Or how about a wet cloth that is wetted with isopropyl alcohol (as this does not harm the phone)?

Living in a place where there are dogs

Q: I have got the scholarship for further studies abroad. I pray fives times a day.

1. The country I am going to, they eat pork and dog meat. This scholarship will be a life changing opportunity for me but I am worried that I need to interact with the local people on a daily basis, like professors and other classmates. Anything haraam I should avoid while interacting with them like hand shake or exchanging things?

2. I need to rent a room. They normally keep dogs as pets in their houses and fridges are also available in the rented houses in which they keep dog meat and pork. Should I use this fridge, stove and how to clean (purify) this place for living here if they kept dog meat in there?

3. I will offer prayer in that room. Explain briefly about the najasat of dogs and their saliva because dogs are everywhere in this country. They are in public places and sitting onbenches that are basically for humans to sit on. 

Purifying walls painted with a paint brush made from pig hair bristles

Q: Yesterday I was having doubts while I was painting my parents house about the paint brush. Today we had half left and when I searched the internet, i found that the paint brush was made from animal hair and it's non halaal. My family members are painting with it before I told them it's najasat because I just found out a moment ago and not yet told them. I have mixed the paint with the brush. Does my house become naajis and what do we do with the remaining paint? If I touch the house with wet hands, does the najasat transfer? This is very distressing. We have thrown the brush but the paint is still left and on the wall. Now must I throw the remaining paint away?