Riba in Islam is not permissible according to the Quran and Sunnah, and definitive scholarly consensus. Riba is one of the major sins. For more, see the detailed answer

It is better not to shroud a man in a chemise, rather he should be shrouded in three pieces of cloth which are wrapped around him, as was done to the Messenger of Allah but if he is shrouded in a chemise, it is permissible.

Salat al-tawbah is proven from Prophet Muhammad (peace and blessings upon him) and it is prescribed when the Muslim repents from any sin, whether it is a major sin or a minor sin. The Prayer of Repentance may be offered at any time, including times when prayer is disallowed.

Wiping over the socks is limited to one day and one night for the non-traveller, and three days and nights for the traveller.When the period ends, it is not permissible to wipe over the socks until you take them off, then put them on after purifying yourself fully with water. You can overcome the difficulty of washing your feet by sitting on a chair, or pouring water over the feet without bending down to wash them.

It is permissible for a sick person to join prayers, so he may join Dhuhr and `Asr, and Maghrib and `Isha’, at the time of the earlier or later prayer, depending on what is easiest for him. Difficulty caused by sickness is one of the excuses which make it permissible to join prayers.