How should someone who prays on a chair in Tarawih prayer align themselves if they sit on it during various parts of the prayer, or during bowing (ruku'), prostration (sujud), Tashahhud, or standing only, knowing that the alignment for someone who sits on a chair throughout the entire prayer is by placing the back legs of the chair in line with the row?

Firstly: Standing, bowing, and prostrating are pillars of prayer. Whoever is able to perform them must do so. Whoever is unable to do so due to illness or old age may sit, based on the Almighty's saying: (Pray standing, and if you are unable, then sitting, and if you are unable, then on your side). Scholars unanimously agree that whoever is unable to stand may pray sitting, and their reward is not diminished if they have a valid excuse. However, if someone prays an obligatory prayer sitting while able to stand, their prayer is invalid.

Secondly: Whoever has a valid excuse for not standing may sit on a chair during the standing posture and perform the bowing and prostrating in their proper forms. As for someone who is able to stand but finds bowing and prostrating difficult, they should pray standing and then sit on a chair for bowing and prostrating, making their prostration lower than their bowing. It is obligatory for anyone praying sitting on the ground or a chair to make their prostration lower than their bowing, and to place their hands on their knees during bowing, and on the ground during prostration if they are able, otherwise on their knees.

Thirdly: Regarding the placement of the chair in the row, the consideration is aligning the row with the seated worshipper's posterior. If the worshipper will be sitting on the chair throughout the entire prayer, then they should align the row with their sitting position. However, if they will pray standing and only sit on the chair for bowing and prostrating, then the consideration is aligning the row while they are standing, and the chair should be behind the row in a position that does not inconvenience those praying behind them.