You cannot permanently lend a book via the standard lending process.
Does the person have a nook? If so, you can download a copy of your book and sideload it to his nook. Then open the book - it will prompt you for your name and credit card number (from your B&N account). It uses that data to create a hash that will match the hash used in the DRM on the book (this does NOT save your credit card number on his nook). Then your friend can read the book indefinitely, and you don't need to buy a new copy of the book (unless you want to).
The recipient would have to provide a working credit card even to get a loaned e-book from B&N. And the loan is only for two weeks.
You might check some other e-book stores that do Adobe EPUB, like Kobo, Sony, Diesel, etc. I believe that Sony and Diesel only do gift cards, not specific e-book titles. Kobo was the first e-book store to allow you to give a specific e-book title, but I don't see the "Send as Gift" button on their e-book pages any more, so maybe they've stopped doing that.
No you can't permanently lend a book. The publishers won't allow it.
And, your friend would STILL need an account with a CC attached to get it. The publishers require copy protection or they won't let B&N carry their books at all. B&N's system requires a valid CC. Period.
Some people get pre-paid cards and attach them to their account. Google now has one via Wallet that's a prepaid-Mastercard in disguise. It's free and never expires. Load it with a couple of dollars and forget about it.
As for being worried about giving out his CC... he does that everytime he buys something. One of my cards was exposed by the bank tha issued it (thank you, Bank of America) and another by a grocery store POS that got hacked. Just keep an eye on the transactions and do NOT use those ATM Visa's; the protection is much weaker and the impact to your finances is much higher. You have to notice the problem (money MISSING from your account) and then convince the bank to put the $ back in your checking account. On a true credit-card, you just have to report the issue and wait while they work through their process.