He should pray the Sunnah first.

In Islam according to the Quran & Sunnah if someone misses the Fajr prayer due to forgetfulness or overslept. But as soon as he wakes up he prays the Fajr prayer is he allowed to pray the Sunnah prayer after.

Prayer | March 25, 2014 4:19 am
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Here in UK, as per ECFR(European Council for Fatwa & Research), we are allowed to combine maghrib & isha during summer,Due to the delayed disappearance of red-twilight & that the Ishaa is too late around 12AM & the Fajr starts at 3AM. So, I would like to know: -1 – If am I permitted to pray in home, alongwith my friends (small Jama’ah), knowing that we guys would be awake at exact Ishaa time every day & also we could wake up for Fajr as well?
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Can a revert sister put a salah book/paper in front of her while praying if she has fears she will make a mistake in the recitation or tasbih?