Advice for one who fell into sin after traveling to the lands of disbelief

The questioner:
I have a brother who was committed; he prayed the congregational prayer, enjoined good and forbade evil, and grew his beard. He used to object to us watching television and would turn it off. He used to encourage us to pray the Fajr prayer and grow our beards. But when he traveled to Britain to study, he sat in an English chair and stayed for about nine months. When he came back to us, there is no power nor strength except in Allah, he had turned on his head. He changed greatly. He started not praying the Fajr prayer in congregation. He abandoned enjoining good and forbidding evil. He started trimming his beard. He also appeared on television. I ask for advice and a strong warning for those who see traveling to the lands of disbelievers for study or other reasons, so that they do not return having heard a copy of their religion.

The Shaykh:
There is no doubt that traveling to the lands of the mushrikin (those who associate partners with Allah) is among the most dangerous things. Many of those who travel, or most of them, do not return safe.

The presenter:
There is no power and no strength.

The Shaykh:
Because traveling to the lands of the mushrikin and residing among them carries a great danger of adopting their morals or falling into what is greater than shirk (associating partners with Allah), Mighty and Majestic is He.

The presenter:
First, my brother.

The Shaykh:
He is in danger of shirk, in danger of their vile morals, and in danger of zina (unlawful sexual intercourse), lewd acts, and drinking intoxicants, among other things.
So it is obligatory to be cautious about traveling to the lands of the mushrikin, whether for study or otherwise. Rather, in his own land here, praise be to Allah, there is much good. So let him stick to studying in his own land, let him be upright, and let him stick to the truth. If dire necessity calls for it, and he is among the people of knowledge and insight, and he has insight in his religion, then let him fear Allah, let him stick to the good and righteous people, and let him be cautious of mixing with the people of evil, so that perhaps he may be saved if he has insight and knowledge, so that he is able to call to Allah and distance himself from the shirk and vile morals they are upon. The Prophet (peace and blessings be upon him) said: And it was reported from him that he said: Whoever associates with a mushrik and resides with him is like him. Abu Dawud and a group narrated it.
So the point is that this is a great danger. When some people embraced Islam, he (peace and blessings be upon him) said: in terms of action. He (peace and blessings be upon him) said: meaning until he separates from the mushrikin. So the point is that mixing with them and residing among them carries a great danger. So it is obligatory for students to be cautious of that and to suffice with studying in their own lands, among their good brothers and among the righteous teachers, except in the case of extreme necessity for things they do not find in their own lands. So it is not permissible to travel except for one who is known for knowledge, virtue, and uprightness, and there should be with them someone who watches over them and observes them so that they do not fall into falsehood and much evil. There is no power nor strength except in Allah. So the point is that traveling to the lands of the mushrikin is a great danger.
So whoever is afflicted with that should not travel except if he has knowledge, he has guidance, and he has insight, so that he calls to Allah, and so that he is among the callers to Allah, and so that he avoids their evil with insight, and is cautious of their falsehood with insight, and sticks with his brothers and is upright with his good brothers in the Islamic centers and places until he returns to his own land. We ask Allah for everyone well-being and safety.