One would be that AIDS is a reality and a way of life for everyone-not just those stricken with the disease. Friends, family, and communities are all affected by AIDS to some degree.
Another point that Sontag makes is that friendship is important,yet has its limitations. While the friends support the man with AIDS, there is really only some things that friendship can help with. It cannot change the outcome.
Sexuality has changed because of the AIDS epidemic. Sontag wants to make the point that all sexual activity is a risk, not just those involved in homosexuality. This group of friends contains both male and female, and at times they have participated in sexual relationships and affairs with one another. The man with AIDS is a bisexual who had both hetero-and homosexual relationships. Sontag wants it to be understood that no one is safe.
Another theme in this work is that writing is a way to live on. The man stricken with AIDS begins a diary after his diagnosis, and his written word will keep him alive.