Is it permissible for the man to go out wearing shorts?
All Perfect Praise is due to Allah, The Lord of The Worlds
It is permissible so long as his Awrah (private part), which is between his navel and knee, is covered. However, the regular wear traditions and modesty are to be observed. And Allah Knows Best
Is it permissible for the mother to offer an Aqeeqah (the sheep slaughtered on the seventh day from the child`s birth)for her son?
Aqeeqah is due on the one obliged to provide for the newborn, and it is permissible for the grandfather, or the mother to offer the Aqeeqah.
I have mixed (halal and haram) money, and I want to purify it. My father is poor, and I want him, my mother, and my mother-in-law to perform Hajj, along with myself and my wife, as they need care due to their old age. Is it permissible to use this money for Hajj, or what should I do with it? Please advise.
If you knew the exact amount of unlawful money, then you should give as a charity, and if didn't then try to figure out the closest amount in order to give it as a charity.
As for performing Hajj, perform it by using your lawful money. May Allah Bless you for being dutiful to your parents and your mother in law and for your attempt to serve them, And Allah Knows Best.
Is the marriage contract considered valid if concluded at home by the marriage official (Ma`zon)?
Yes, it is valid as long as it is registered at the court.