The following is a brief article in Urdu regarding the ruling of Qiyam for someone who is unable to do Rukoo and Sujood.
To read or download, click on the following link: ruling-on-standing-for-someone-who-cannot-do-sajdah
UPDATE (8 DEC 2015)
The following Fatwa written by Mufti Taqi Uthmani Sahib affirms the position highlighted in the document above. Further, it sheds light on the ruling on performing Salah on a chair.
Click on the following link to download: Fatwa Regarding Salah on Chair and Qiyam for one who cannot do Sajdah (By Mufti Taqi Uthmani Sahib)