Paying zakaat once one acquires one's share of the inheritance

Q: Regarding inheritance/working out zakaat, an estate has only money, no business, etc. 

The house and car of the deceased was already given to his wife in his lifetime - it was accepted and agreed by all during his lifetime that it belongs to his wife. 

The person passed away 3 years ago - the estate got sorted out last week and shares were given. 

Must the zakaat be give for all the previous years while they were sorting out the inheritance? 

And when do they pay zakaat for the share that was received? Should it be paid now or would they wait for a year to pay it?

Making tayammum if it is not possible to make wudhu by oneself and there is nobody to assist

Q: I found the below statement about tayammum online, is this true? 

"If performing wudu causes extreme fatigue or is too difficult due to your condition (e.g., mobility issues or severe pain), you may: Seek assistance if someone can help. Use tayammum if assistance isn't available or feasible." Is this true? 

Leaving unwanted furniture for the dirt truck to pick up

Q: My mother complained that the bags that people put next to a tree on our road gets collected quickly and that we are needlessly keeping unwanted furniture etc. in our house when it can get collected quickly and for free. She threw some of our bags in that area. 

I told her fly-tipping is wrong but she says that everyone does it. Fly-tipping is considered illegal and finable. I’m worried that she may be sinning by doing so. Does she have to repent? I’m also worried that I may have aided her as she asked for a bag to collect the waste to throw out and I reluctantly gave her.

Husband telling his wife "from now on if you tell a lie then divorce"

Q: My husband said in an argument when he was in a lot of anger because I hide some things from him. He said from now on if you tell a lie then divorce. And asked me to say these words from my mouth but I refused and started crying. So after that incident we are living happily but telling a lie means smaller lies or hiding daily basic routine things to him. So in that case I have tell lies in daily routine. After one years time, like I hide somethings, that spoil his mood so in that case is our divorce happen or not?