I wouldn’t suppose that people are required to inform steam that they’re dead. Therefore, I’d assume the easiest way to bequeath games/DLCs, etc, is to get a wishlist from your loved ones, and then gift all of those games prior to death on a credit card that you might not be able to pay, due to being dead. Steam gets the money, the CC company gets shafted. Alternately, share your credit card details with a loved one and that list, and have them order within hours of your death (this depends on whether or not you were plausibly alive when those CC transactions took place)
The timing of the click captcha loading is randomized and it probably is looking for human-ish cursor movement? (Like you’re probably moving your hand in imperceptibly small ways that are difficult to replicate). Clicking before it loads and doing it repeatedly probably triggers detection.