Answering the question, Dr. Rajab Abu Maleeh, stated:

As long as the pilgrim has performed Hajj and observed all its pillars and conditions, his Hajj is accepted and it is considered as the obligatory Hajj.

however, what is stated is based on performing all the rites of Hajj and avoiding its nullifiers, because falling in any of the invalidators of Hajj such as not standing in `Arafah, requires other rulings.

If  the Hajj is valid, then we do not have to repeat it but it is advisable to offer another one by way of sunnah.

however, helping a Muslim perform his or her obligatory Hajj may be better than offering another Hajj by way of sunnah after performing the obligatory time of Hajj.”