Three talaqs take place by giving three talaqs in a single meeting. It is agreed upon by Sahabah, Tabi’een and majority of Fiqh and Hadith scholars. Declaring Salafis three talaqs as one is totally wrong. It is not lawful to practice their fatwas. Hence in the question mentioned above if the husband has given three talaqs in a single meeting then now there is no way out to marry the wife except a valid halalah. If you practice the wrong fatwa of the Salafis your wife shall not be halal for you.
ذهب جماهير العلماء من التابعين و من بعدهم – على أن من طلق امرأته ثلاثاً وقعن و لكنه يأثم . (عمدة القارى: 20/234، كتاب الطلاق، ط: بيروت)
Allah knows Best!
Darul Uloom Deoband