He is eligible to shorten his prayer once he leaves the boundaries of the city of his residence.
https://www.youtube.com/watch?v=f_5PifGhOTY

My husband will go in shaa Allah to Algeria for two weeks. Can he shorten his prayers from the moment he goes. (Not when he prays in the mosque)

Prayer | January 19, 2016 4:17 am
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If one forgets to say one of the takbeers (not the opening one) do we just do the prostration of forgetfulness before the final salaam?
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My father wants to pray tahajjud but he may not be able to do it on regular basis. Knowing that Allah loves deeds that are consistent he is worried that if he is unable to do it every night then he might be sinful. What should he do?