I've never tried to grow brugmansia personally, and I know of only one person who has successfully grown them from seed. They're notoriously hard to germinate, and they're easily enough available as a pre-rooted plant in garden centres. Plus, they grow virtually all over the continental U.S. as an ornamental plant, so I've never had a need or desire to grow one out. I have, however, consumed a brugmanisa flower before, and it's not a entheogenic experiment I'd care to repeat- if I ever did it again, it would probably be a very small segment brewed into ayahausca, as is done among some Amazonian tribes. Atropa alkaloids are frightening, and that's saying something: virtually nothing frightens me.
First, I assume you have in your possession the seeds, and not simply the pod that contains the seed. If it's the latter, crack it open. I'm not sure of the shelf life of the seeds themselves after they've been removed from the pod, so I can't comment on their viability if the seeds were shipped by your friend. Tree daturas seeds can be stored for a while though, so far as I know, because they can enter a dormant state until conditions are JUST right to grow.
I do know of a few things that could help, as the aforementioned friend gave me a rundown of what he did. First, the seedling needs sandy, loamy soil. Peat moss is good, as is a sand/organic soil mixture. The soil should be -slightly- moist, but BARELY... These plants generally germinate better in drier areas, and they can enter a dormant state when there is no moisture. The main thing you need is HEAT. Tree daturas seem to love heat even more than the herbacious ones. If you have a heating mat, that's ideal. Aside from this, I can't really help you much... Atropine-containing plants aren't my cup of tea, as I said.
If your friend can procure seeds, see if he can get you a cutting, with some live growth toward the bottom to be removed for rooting (heel). This is your best bet, as these plants do well when planted as cuttings. It's difficult to germinate these babies, as you've already discovered. Good luck though on whatever you decide to do, and if you have any more questions, I'll do my best to answer them. Angel's Trumpet really is a beautiful (if deadly) tree.
~Ethno