Answered by: Maulana Shadman Ahmed
Praying Salah on the chair; if one can stand up then how should he pray?
In the name of Allah, the Most Gracious, the Most Merciful
If a person can stand but not do the sajdah, they should pray the entire prayer sitting down with indications. If a person is not able to sit on the floor, then they can sit on the chair. They will indicate for ruku and sajdah making sure that they elongate lowering their head and stretch the indication for sajdah more than the ruku.
Only Allah knows best
Written by Maulana Shadman Ahmed
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Muḥammad Amīn `Ibn ’Abidīn, Radd al-Muḥtār ’Alā al-Durr al-Mukhtār, Vol. 1. Pg. 442. vols. (Dār al-Fikr, 1252H); Burhān Al-Dīn Maḥmūd b. Aḥmad, Al-Muhīṭ Al-Burhānī fī Al-Fiqh Al-Nu’mānī, Vol. 2. Pg. 142. vols. (Dār al-Kutub al-’Ilmmiyyah, 616H).