What is the ruling on one who slept while firmly seated on the ground, regarding nullification of ablution?
The default ruling regarding sleep is that it nullifies ablution. An exception to this is one who slept while firmly seated on the ground; his ablution is not nullified by sleep if he wakes up while still firmly seated on the ground. And Allah the Almighty knows best.
Does nosebleed during the day in Ramadan affect the validity of fasting?
A nosebleed does not affect the validity of fasting unless some of the blood reaches the body cavity or the person intentionally swallows it. In such a case, their fast is invalid, and they must refrain from eating and drinking for the rest of the day and make up for that day later.
What is the ruling on taking a medication tablet sublingually during the daytime in Ramadan?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
Taking a medication tablet sublingually (under the tongue) during the daytime in Ramadan does not invalidate the fast, since it does not reach the internal cavity (al-jawf) through an open passage.
However, if the tablet dissolves and any part of it is swallowed, then the fast is broken.
And Allah, the Exalted, knows best.
What should someone do if they fasted for 30 days in their country, then traveled to a place where people are still fasting?
If a person completes 30 days of fasting in their country and then travels to another country where people are still fasting, they should continue fasting with them until they observe Eid. Even if they have already completed 30 days, he/she should abstain from eating and drinking and join the people of that country because he/she has now become part of that community.