Is it permissible to give lessons to mixed students of the seventh grade?
It is impermissible to give private lessons to mixed students since such an act leads to serious consequences for the students in this grade are teenagers.
Is washing the private part after urinating (Istinjaa`) a condition, and is it done with water and soap, or with water only?
Istinjaa` is obligatory for removing impurity, and it can be done with toilet paper, or a stone, or water. It is preferable to do Istinjaa` first with paper, or stone, or the like, then to wash the private part with water until making sure that the impurity has been removed. Using soap is not a condition, but there is no harm in doing so provided that it is washed off with water. It is also permissible to use either water, or paper if impurity is removed by any.
In life insurance with the Potash Company, enrollment is mandatory, and employees have the right to receive a cash amount from the insurance for surgeries and illnesses while employed by the company. Is the amount given by the insurance in this case permissible (Halal) or prohibited (Haram)?
Since the insurance is compulsory, then what the insurance company pays in return for medical treatment is similar to donation, and I pray to Allah The Almighty that this is lawful even if this service is deducted from your salary in return of it, so in this manner you take back some of the amount you paid in form of above treatment. And Allah Knows Best.
What should a sick person, who is incapable of fasting, and who didn`t make up for missed fasting days, do?
One who has missed fasting days is obliged to make up for them, but if he/she wasn`t able to because of an incurable disease , or old age, then he/she has to pay a ransom which is feeding a needy person for each of the missed fasting days. And Allah Knows Best.