What does "All the deeds of the son of Adam are for him, except fasting" mean?
The Prophet ﷺ said: "Allah, the Almighty, said: 'Every deed of the son of Adam is for him, except for fasting; it is for Me, and I shall reward for it." [Agreed upon]
This means:
● Every deed of the son of Adam may be affected by showing off (riyaa’), except fasting, because only Allah knows whether a person is truly fasting or not.
● The reward for all deeds is known—one good deed is multiplied tenfold—except fasting, as only Allah knows its true reward.
Is it permissible for a mother to stop her daughter from marrying a respectable, God-fearing young man because he isn't college/university graduate?
It is impermissible to deny a woman her right in getting married except for a lawful reason, and problems can be solved through dialogue. However, she can file a suit in order for the judge to have a say in that regard.
Is it a condition that a woman should untie her locks while making Ghusl (ritual bath)?
Ghusl from Janabah (ritual impurity), or menstruation obligates that water reaches the roots of the hair in order for the Ghusl to be valid, but if it doesn`t, then hair locks must be untied for water to reach them, and for Ghusl to become valid.
A pious man proposed to me and my father was hesitant in this regard because he is black, am I sinful if I accepted his proposal?
If the suitor is pious, color isn`t a drawback. However, try talking to your father kindly, so that he approves of your marriage with contentment, and that is better for you.