There are different personality types that are stated by the MBTI. The weakest socially according to the test is the mixture of Introversion, Thinking, Sensing, and Judging also known as ITSJ. An introvert is usually happy doing things on his own or being with a small group of people that he trusts. If you have to bring him to a place where does not know anyone, he may have a hard time fitting in.
He will also feel uncomfortable the whole time. Take note that the personality type is also a bit controlling. Everything needs to be planned or prepared or he would not like it. This can be a hard personality type to understand and to appreciate.
Each of the personality types have areas of weakness, even socially. However, a combination of Introversion - some avoidance of social contact and a tendency to be self-obsessed - with a desire for predictability, for facts, familiar processes, might well lead to a limited, less joyful life-style. This description would be nearest to type ISTJ, Introversion/Sensing/Thinking/Judging.
Such individuals prefer to be planned and organized rather than spontaneous and flexible. ISTJs are sometimes referred to as Inspector personalities because of their focus on details and interest in doing things correctly. This can be quite an unattractive social personality. If you think of people diagnosed as having Asperger Syndrome, they would come near to this combination of personality tendencies.