Answer
(Fatwa: 1560/10012/L=1431)
It is better to offer the sunnah salah in journey if one feels comfortable. If one does not feel comfortable and is in hurry, he can offer the fardh and wajib only and leave the sunnah. If you are going to the house of your relatives, and their house is situated at the distance of 77.25 km or more, and you do not intend to stay there for fifteen days, then you should do qasr there.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband