If your little brother has take prohormones (im guessing since you said little brother hes younger than 19) get him up to the nearest hospital and tell them whats hes done and get him fully checked out.
How old is he?, what exactly did he take?, how long did he cycle it?, did he use a pct afterwards?, and what did he use for pct?
Heres some info on the sides of PH's for under 21's
When you are under 21, your endocrine system is still developing. This should be obvious as you are still going through the end of puberty, getting acne, etc. During this time peroid, supplementing with extrogenous hormones is EXTREMELY DANGEROUS. There is potential for very serious and long term side effects to occur. I hear all the time some of these people saying that "I've stopped growing, so it's okay". No - it's not okay. There are many other potential side effects besides growth plates. Here is a list of a few.
1) Premature closing of growth plates. This one is the most known about. Even if you think you have stopped growing, there still is a potential for height increase over time. I have known people who are 18+ who have continued to grow in height. Scientists know that growth plates don't fuse completely in some cases until individuals are past 22. Don't be deterred just because you haven't grown taller in awhile.
2) Impotence. Supplementing with hormones while you are still growing can potentially cause PERMANENT impotence and fertility issues in teenagers. When you add testosterone, estrogen and a wealth of other synthetic androgens to your body it can cause problems with your normal testicular growth and function. Remember, some of these effects are more than just temporary.
3) Liver/Kidney Problems. I hear all the time teenagers say "Well my friends used it and they got big and nothing happened to them." Really? How do you know? Have they been to a doctor and had their liver and kidney values checked? I doubt it. Just because a person looks okay on the outside, doesn't mean that they could have a host of problems on the inside. Liver and kidney damage is nothing short of serious. This can occur even in people who are past their teen years.
4) Gyno or "bitch tits". I believe this using androgens in teens can really increase the risk of gyno. Gyno has been known to happen naturally in many teenagers because of already fluxating hormones. When you add more hormones to the mix, you dramatically increase the problems. Remember that once you have gyno, its very hard to get rid of unless you take the proper precautions up front.
5) Hair loss/acne/prostate aggrevation, etc. All of these can be increased and agrevated with external androgen use. Have you ever seen a 20 year old going bald? It's not pretty. Don't think it can't happen to you.
6) Brain function. It is well known that hormones play a role in development of cognative brain function. Adding external hormones when your brain is still developing could be a disaster waiting to happen. How can you now many years down the road there won't be problems? | 
