If a traveler enters the mosque and finds them praying the night prayer, and he has not yet prayed the sunset prayer, and he joins them, and when the imam stands for the fourth unit he sits down, is his action valid or what?

The questioner : A man entered the mosque while he was a traveler and found them praying the night prayer, and he had not yet prayed the sunset prayer, so he joined them. When the imam stood for the fourth unit, he sat down. Is his action valid or not? Please issue a ruling for us, may Allah reward you.

The Shaykh : The stronger opinion is that his action is valid. That is, if you catch up with the imam while he is praying the night prayer and you have not yet prayed the sunset prayer, you join him. When he stands for the fourth unit, you sit down, intend to separate from the imam, complete the tashahhud, and say the closing salam. Then you join the imam in the remainder of the night prayer. This is the stronger opinion. Some scholars said: No, pray the sunset prayer first, either alone or with those with you, and then join the imam in the remainder of the night prayer. Some scholars said: Join the imam with the intention of the night prayer, and when you finish it, pray the sunset prayer. These are three opinions from the scholars, and the strongest and most correct of them is the first opinion: that you join him with the intention of the sunset prayer, then when he stands for the fourth unit, you sit down, recite the tashahhud, say the closing salam, and join the imam in the remainder of the night prayer.
Yes.