Does passing wind, from the anus without a smell, invalidate prayer?
If a person is certain of having passed wind even if it was with no smell, then both his/her ablution and prayer are invalidated, thus he/she should remake ablution and re-perform prayer.
Is the son of the sister by breastfeeding considered a mahram in Islam, and is it permissible for a woman to go for Hajj with him?
Everything that is prohibited by lineage is also prohibited by breastfeeding. The son of the sister by breastfeeding is considered a mahram, just like the son of the sister by blood, and it is permissible for him to be her mahram for Hajj and Umrah. And Allah Knows Best.
What is the ruling on one who sees moisture on his clothes and doubts whether it is semen or pre-seminal fluid (madhy)?
Whoever finds moisture upon waking from sleep and doubts whether it is semen or madhy, and cannot distinguish between them, he may choose between them and act according to his choice. If he wishes, he can consider it semen and perform the ritual bath, or consider it madhy, perform ablution, and wash what it has soiled. This is because if he fulfills the requirement of one of them, he is definitively free from it, and the default is his innocence from the other. And Allah the Almighty knows best.
What is the ruling on fasting for those with diabetes, heart disease, high blood pressure, kidney disease, or ulcers?
● A sick person who is completely unable to fast is exempted from fasting and must offer fidyah (feeding a needy person), as Allah Almighty says {what means}: "and [in such cases] it is incumbent upon those who can afford it to make sacrifice by feeding a needy person." [Al-Baqarah/184]. They are not required to make up for the missed fasts.
● A sick person who can fast on some days but not others should fast when able and make up the missed days after Ramadan when possible. No fidyah is required in this case.
● If fasting during the long, hot summer days is too difficult for a sick person, but they can make up the fasts during the shorter, cooler winter days, they should break their fast and make up for it when they are able, without fidyah.