Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother in Islam, thank you for showing concern toward your Muslim brothers and for your attempt to help them.
Hajj is one of the Five Pillars of Islam. Almighty Allah enjoined it, saying, (And pilgrimage to the House is incumbent upon people for the sake of Allah — (upon) those of them who can afford means to it) (Aal `Imarn 3:97).
Thus, those who can afford the means are obliged to perform Hajj. Being in the company of Shiite Muslims is not an excuse for not performing Hajj. A Sunni Muslim can even take advantage of this opportunity to clarify the truth for them, if there will be a chance to do so.
Answering this question, the Standing Committee for Islamic Research and Ifta' stated,
They are obliged to perform Hajj if they are financially and physically capable, even if they have to travel in the company of Shiites. However, they should be extremely cautious, lest they be deceived by the false Shiite doctrines. They are also obliged, only if they can, to kindly advise them to follow and adopt the doctrine of Ahl-us-Sunnah wal-Jama`ah (those adhering to the Sunnah and the main body of Muslims). This is based on the Qur'anic verse in which Almighty Allah says, (Call to the way of your Lord with wisdom and goodlyexhortation, and argue with them in a way that is better) (An-Nahl 16:125).
Excerpted from www.alifta.net