That is the only vaccination I can get without a skin test. I usually get one shot as soon as possible and then a booster in January. They make me wait 30 minutes after vaccination just in case. I had the flu two years ago before I could get the shot and ended up really sick, which is now why I get it twice a season. I'm a bit concerned this year because the vaccine was only about 30% effective, but so far, haven't gotten the flu.
He actually sounds worse than me. I developed asthma when I was in elementary school. It started out fine, but got progressively worse. I had bronchitis and at one point pneumonia after the diagnosis in elementary school. I got really bad in middle school and was hospitalized at one point with my asthma. I got the allergy shots after testing allergic to so many things and had to have one shot in each arm because of all of the allergies. In middle school, I developed food allergies which then got worse in high school and are still bad now. I understand the mold/mildew allergy because I am just as bad. But the shots toned down a lot of my other allergies so I don't have the same problems that your brother does with not being allowed to have fabric in the room, though I'm as bad as he is with the cigarette smoke. And I was never allergic to pet dander. Now that I'm in college, I have severe but well-controlled asthma that my doctor thinks is getting better. I take two controllers daily, and I keep oral steroids on hand. I also have a portable nebulizer that I keep with me, as well as an inhaler and epi pen. My worst problem is the perfume/cologne. Nebulizer didn't work last week, and that's when the school called 911. I know where all the perfume shops are in WDW and avoid them. I also avoid smoking areas. But doctor said yesterday that I'm a lot better than I used to be, so I'm hoping that in my 20s I'll start leveling off a bit.
I try not to let it stop me, though. There is some stuff that I won't do. Visit a country without good hospitals, for one. Trek into the middle of the woods with no electricity and no cell phone signal and no nearby hospitals. But overall, I try to control my asthma, not let my asthma control me.
I've had all of my vaccines minus the varicela booster, which my doctor exempted me for when I went to college. After I went into anaphylaxis, he said no more vaccines for a while, flu shot only. I cannot get Tdap or menigicocal again. I don't think I need another meningicocal, though. So Tdap is basically the one I have to worry about. Any others that I might need I have to get skin tested for.