A young woman (college age) is raising her nephew. Her sister, the boy's mother, died in an epidemic when her son was a baby. The same illness left the father with permanent physical change: an appearance very different from his former one. Out of discomfiture over this, coupled with grief over losing his wife, he's left the child in the aunt's care. He provides his sister-in-law with money to attend school and care for the child. But there's a stated (not legal) agreement that she will pose as the boy's mother, and teach him as he matures that his father has passed away.
The aunt is a devoted caretaker, and goes along mostly out of sympathy. But a year or so after they reach this agreement, she balks at continuing it. She wants her nephew to know his father, what became of his mother, and what their true relationship is. Regardless of possible consequences, she doesn't want to lie to her nephew or other adults about the situation any more.
My question is: how much would a child of two or three grasp an adult's attempt to basically "retool" a relationship like this? Would it be confusing? Traumatic? Or have little long-term effect at such a young age? Would he even differentiate much between the concept of "Mom" vs. "Aunt"? Would it be jarring for him to find out at this age that his "dead" Dad is really alive? Or that they don't much resemble one another?
I've checked out the tags here re: Adoption, custody, child rearing, and child development. None really cover this scenario. I've searched phrases like: "how young can a child understand family relationships" and "child's knowledge at age three." Lots of interesting stuff, but again, nothing specifically addressing this.
Any help is appreciated, even if it's just better search terms. :o
**[ETA- Thanks for your input, Folks! I definitely have more to go on than I did before. :)]**