When an animal (including us) acquires an infection of any kind, the body produces an antibody very specific to that bug. There are about 150 different strains of bad colds in the world. Each time you get a cold, the body produces an antibody for that infection. Each antibody has the capability to attach itself to a specific virus or bug, then the bodies immune system sends white cells, (lymphocytes) which can find the antibody they are programmed to locate and destroy the infecting partial. The antibody stays with you the rest of your life. So the next time that specific cold virus gets into your system the body can attack it immediately and it won't get out of hand and make you sick. This is why older people get fewer colds than children. They have already gotten most of them and can only be made sick by newer ones they haven't gotten yet.
When the Aids virus is acquired, the body does the same thing as before and produces an antibody to fight it. The problem with Aids is that it mutates quickly. Each mutation requires the body to come up with a new antibody. If a person is infected to begin with numerous strains or variations of the virus, the body really has to work hard to fight it. Each time the virus mutates it can mutate into many different strains, and the body has to work extra hard.
Something that took scientists a long time to realize was that when one becomes infected with HIV, the body proceeds to fight it hard from the very beginning, but the body system is unable to catch up with the mutations, so it CONTINUES to have to fight hard continuously. After around 8 years of this hyper activity of the immune system, the parts of the bone marrow and all the related systems that are responsible for producing the "white cells" eventually ware out and the white cell (or T cell) production runs down. This is the first time that the infected party begins to show real signs of what is known as AIDS. (Acquired Immunodeficiency Syndrome) The immune system can no longer create enough T cells to fight off much of any infection at all. So things that our bodies normally fight off easily, things that are always around us in the air and such, are able to multiply and cause massive infections that the normal body would never allow to happen.
This is generally indicating that your friend's complaints are not related to AIDS at all. There are certain diseases that are the normally the first ones to show up. Such things as pneumasisis phenomena which is generally the first thing to hit. pneumasisis is a very common microscopic fungus that is present everywhere in the air and ground. Normally we can fight it off with no problem, but when the immune system can't produce enough T cells to fight normal things we breathe in all the time, the pneumasisis finds a niche which it can grow rapidly, the nice warm moist insides of our lungs. Thus it explodes in production and produces phenomena. This phenomena is easy to fight, but if the doctor doesn't realize what it is in time, it is too late. Also the treatment for pneumasisis phenomena is a sulfur drug. Some people are allergic to sulfur drugs and they usually die quickly from pneumasisis phenomena.
In my case, we didn't find out about my infection of AIDS until I developed the pneumasisis phenomena. By that time my body had wore out it's system and they gave me about 6 months.
I managed to survive for about a year, my body still fighting as hard as it could, when the body wore down all together and the T count dropped to 0. Amazingly I stayed alive. About a year later, they came out with the first of the protease inhibitors.
Viruses (all kinds) can not reproduce themselves. They have to get themselves into a "host" cell of some sort and they utilize the nucleus of that host cell. By splicing themselves into the DNA of the host cell, they use the reproductive system of the host cell to replicate themselves. Of course in the process of splicing into the DNA of the host cell the host cell initially looses it's capability to do what ever it was supposed to do. Then after the virus replicates, the host cell dies.
In order for the virus to get into the cell without destroying the cell, it must attach itself chemically to a "receptor" chemical on the surface of the cell. Each virus uses a different receptor. A protease inhibitor works by plugging the specific receptor that the infection needs to use to get into the host cell. If the virus can't get into the host cell, it can't reproduce.
Of course there are problems, considering the incredible number of cells in the body, the number that die each day and new ones being produced, that is a lot of receptors that have to be plugged. We have to balance the dosage of the protease inhibitor drug so we get enough drug to do the job without being so much that it poisons the body. These drugs are after all toxic to our system. Put enough drug into the body to take care of all the receptors and we poison the body to death very quickly.
The problem with HIV is it uses one of the T cells to do it's reproduction for it. Specifically the T4 lymphocytes. The T4 lymphocytes is responsible for attacking it's own large group of infections. In addition it is somewhat of a commanding general for many of the other T lymphocytes and controls much of the bodies immune system. So when the T4 system fails, much of the rest of the system becomes week too.
In my case, after beginning the protease inhibitors, my body's immune system was able to recover somewhat. I am now running a T4 count of a bit over 300. The normal healthy person has a T4 count of between 500 and 5,000. The best I can do is 320. So it is VERY important that I don't get any infections if I can at all help it. Even a cut on the finger MUST be treated at once, otherwise it will become infected very quickly.