Welcome to the site Greg
Availability being one question:
It is very easily the possibility of availability in my opinion, most of these herbs that work phenomenally well can be purchased at just about any and every vitamin store, i.e. GNC, WALGREENS, VITAMIN SHOPPE, CVS, SCHNUCKS even. They are very affordable the most i believe is Pueraria Mirifica which is by far the most popular one and all the rage right now. You can get it at various places (only online for this particular herb) most popular i believe is AinterolHerbs.com or amazon AinterolHerbs and get the same result. Its the most powerful estrogenic herb on the market and is strong stuff. Me personally would recommend building up the strength of any dose over 1000 mg a day by taking 500mg (1 capsule a day) for a week or two then progressing if he desires to do so.
Most popular herbs I believe and these are all found at most if not all stores are
Red Clover (what i understand is probably the strongest estrogenic herb behind PM, i take it 3x a day and within a week my skin was incredibly softer and even noticed some fat added on to my butt

)
Fenugreek (another estrogenic herb, often used to build milk ducts in a womans breasts as well as help with milk in the breast during pregnancy)
Saw Palmetto (used for prostate health but i take about 6 a day and at a higher dose it acts as a testosterone blocker helping aide in the breast development by allowing estrogen levels to rise)
I have heard others using Black Cohosh which is for womens menopause to help with estrogen levels and balance of it in women, honestly in my opinion its very dangerous to your liver and very well not worth the effects if its going to be putting your liver or kidneys into danger zones.
There are many others but i believe the first three along with Pueraria Mirifica are the best to use. Many use only PM (pueraria mirifica) and see absolutely amazing results, you can go to the ainterolherbs forum to see others who have spoken on their progress if you choose to do so outside this forum heres a direct link
http://www.ainterolherbs.com/forums/Foru...Encouraged
Also a product in which I am very fond of that is also inexpensive while many on here have been skeptical and some very rude all because i mention it often (pm is not the only thing that works lol) is Natureday.com its a wonderful product, i use their soap just cause its slower (lather it on chest set for a few min and wash off in shower or towel or whatever you choose) i have used their cream and drops as well but it honestly worked too fast and me being 26 with a gf who has no clue i dont want to rush the process for personal reasons. Their cream i believe is 35 after shipping/taxes and soap 21.00
As to what others say especially about implants, implants on a man are very painful i hear because most don't accumulate breast growth much at all before doing so and can only go to a specific CC implant also yes, stretch marks and other ugly marks like scars also personally, breast implants are hideous, they dont move, they dont jiggle, they are just basically pitcher mounds on a chest lol who wants that, if you're going to get breasts definitely take the time to go the natural route. Implants can go from 5-10 thousand dollars, im sure no one on this site has spent anywhere near even 2000 on their herbal supplies over the year(s).
One thing to certainly remember is, while these herbs are 100% natural, and not dangerous by any means, most are capsules which go through the stomach, liver and kidneys. Altering your hormones can cause a great deal of harm to the body if you push the limits over a period of time, do not take more then recommended without building up a tolerance for it to your system. Cause while it is all natural, too much of a good thing can be bad.
Also hormones have a way to rewire the brain at times (making one more emotional, sensitive, even in my case at one point making me depressed cause i was so convinced i was transgendered that it nearly ended my relationship) this stuff will grow him breasts in due time, but in due time be sure its what you want, cause while fat redistribution will redistribute back to a man's areas as well as skin softening diminishing and mental changes may go back to normal after stoppage, breast growth is permanent, and should be thought about wisely and not emotionally (he should not want it because he thinks it will be sexy/hot, he should think about summers, pools, lakes, etc, how will people react and how will that make him feel with people staring or the paranoia of others staring.
Not to be lengthy just assuring you herbs do work, do your research on the site many intelligent people on here who i honestly would probably trust more than a doctor when it comes to this stuff, dont be shy, ask questions, do your homework have him do it as well, and if its what he wants in the end, then enjoy the journey, support him, encourage, and cant wait to see updates