"Some elderly people come to a point where they don't want to deal with that anymore or they can't," Ramnani said. "So the children just have to deal with the stress of making sure bills are paid, what the investment accounts are doing—things like that."
Andrea Blackwelder, a certified financial planner and owner of Wisdom Wealth Strategies, says one problem she encounters is a lack of estate planning, including such aspects as updated wills, assigning power of attorney and a living will.
Read More25% of Americans save $0 for retirement
"A lot of times it comes down to preparation," Blackwelder said. "The [children] have to put together documents in case something does happen to the parent."
She pointed out that even if a trust is established as part of estate planning, sometimes the person's assets have not been retitled in the trust's name.
"People go through the process of drafting a trust, but nothing, including investments, has been put in the name of the trust," she said. She recommends a team approach: making sure the person's accountant, attorney and financial planner are all involved in synchronizing an estate plan.