Wealth earned through deception

Q: One person is asking for Help for his sons health. We gave him (not only me but so many others also gave) some money. Later we came to know that, that person is a fake and he did not have any kind of problems and he doesn't have a child as well. Due to his bad lucky one day, I saw him and spoke to him. He was earning money like this for many years and when I was asked him didn't you fear Allah he said yes I do. When I told him that earning money like this is haraam, he gave me a wired answer. After hearing the answer I was totally confused and I am totally confused. He said if he earned 1 lakh money that way, he will donate some amount as a Zakaat to purify the money. In this way he will be earning halaal income. 

Is this true? He said if your earn money unlawfully like interest and many other sources, if you give zakaat or donate some money, it will purify the money. Please guide me?

Starting a business through begging

Q: One of my uncle earned his money by begging and now he started the hotel business. Obviously the total money he invested in the Hotel was came from his last job "Begging". But he did all the hard work to make him successful man in the hotel business. I know he was doing charity to purify the money. Is this acceptable and will purify the money? By starting the business through begging did he do any sin?

Performing Salaah after touching a person who uses perfumes which may contain alcohol

Q: Just before salaah was started by the imaam, i gave a hand to someone. When I smelled my hand I smelt some perfume odour. The person's hand was dry, in this case if the perfume he used did contain alcohol or any other impure ingredients did they transfer to my hand? Is my Salaah valid?

Hadith regarding Nabi's (sallallahu alaihi wasallam) nikaah to Hazrat Aasiyah (radhiyallahu anha)

Q: Please inform me regarding the nikaah of Nabi (Sallallahu Alayhi Wasallam) to Hazrat Aasiyah (Radiyallahu Anha) In jannah. Someone told me that all those that never shaved their beards in the world will witness the nikaah. Is there any hadith with regards to this? If there is, can moulana please quote it for me?