In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
What do you mean by qualify as a musafir?
In general, a musafir is one who undertakes a journey of 48 miles/78km or more. The concession of qasr (shortened) Salatwill be upon leaving the housing vicinity of his area.[1]
And Allah Ta’āla Knows Best
Mufti Saeed Ahmed Golaub
Islamic Solutions
Jamaica
References
[1]:وَيَقْرُبُ مِنْهُ مَا اعْتَبَرَهُ الشَّافِعِيَّةُ مِنْ التَّقْدِيرِ بِمُتَابَعَةِ الْمَشْيِ لِلْمُقِيمِ يَوْمًا وَلَيْلَةً وَلِلْمُسَافِرِ ثَلَاثَةَ أَيَّامٍ وَلَيَالِيهَا اعْتِبَارًا بِمُدَّةِ الْمَسْحِ، لَكِنْ قَدْ يُقَالُ لَمَّا ثَبَتَ أَنَّ هَذَا الْخُفَّ صَالِحٌ لِلْمَسْحِ عَلَيْهِ لِلْمُقِيمِ قُطِعَ النَّظَرُ عَنْ حَالَةِ السَّفَرِ؛
الدر المختار وحاشية ابن عابدين (رد المحتار) (1 / 263)