Mix finances and family, and the results are complicated and will often leave somebody angry or feeling taken advantage of.

Here’s exhibit A. In a recent online chat, a reader described an issue that some of you might easily identify with.

The background: He’s single and in his 20s. He makes a good living and feels obligated to help his parents, who are still working but have pushed back retirement because they can’t afford to leave their jobs. “I have been a firm believer for years that I have a responsibility to take care of my parents,” he wrote. “I try to treat them to things, take them on vacation, and just be kind and generous every way I can. They sacrificed a lot when we were kids and I feel like they deserve a gentle ride to the finish line.”

The conflict: The guy’s married sister and her husband, both working, regularly accept monetary gifts from the parents. In fact, the parents even traded automobiles with the couple because the sister and her husband didn’t want to run up the miles on their cars. “I realize that a gift is not a gift if there are strings attached, but it turns my stomach to see my parents take my generosity as an opportunity to give more to my sister and her husband. I never thought they were the type. It also infuriates me to see my sister accepting those offers. She is 25 and should know better.”

The dilemma: The son is feeling like a sucker and is wondering if he should continue his generosity toward his parents. “How can I get over the feeling that there is a constant wealth transfer from me to my sister rather than just me helping out my parents? It is really eating away at me. Should I stop giving to them? Should I even bother to say anything?”

Let me start with his first question.

I don’t see a transfer of wealth from him to his sister. This guy’s money is going directly to help the parents. His efforts are not in vain, at least from the information provided. His parents are reaping the benefits of his financial assistance and that’s not a waste of money. It’s a good thing.

Okay, so how do you stop feeling like a chump if you’re in a similar situation where you’re giving to not-so-wealthy parents who seem to be financially indulging another adult child you think unworthy?

Understand what altruism is. Merriam-Webster defines it as an unselfish regard for or devotion to the welfare of others. It doesn’t mean to give only if the recipient does everything you think is right or just.

So, no, I wouldn’t advise this young man to stop being who he is: a wonderful son who feels grateful for what his parents did for him. If you can afford to take your parents on a vacation, treat them to dinner or pay a bill, keep doing what you’re doing. Besides, if the money is given without any strings attached, what a sibling or another relative gets from your parents shouldn’t matter. It’s theirs to do with what they want.

But let me throw a caveat in here. I would pay close attention to make sure that there are no signs of fraud. In a recent survey, the Investor Protection Trust found that among the top abuses of seniors was the theft or diversion of funds or property by family members. So you should be concerned and take action if you think your parents’ resources are being depleted by a selfish or conniving sibling.

Here’s something else I’ve learned over the years. You never know what’s really going on in somebody’s finances. Outwardly, the sister and husband could look like everything is great (two jobs, two cars, etc.) but maybe they are struggling. Perhaps the sister is like many young adults buried under student loan debt. Perhaps the parents are privy to what’s going on with the couple and feel compelled to help them.

The bottom line: Unless you fear some form of financial abuse, I wouldn’t say anything to the parents about their generosity toward an adult sibling. I might, however, inquire about how they are saving and planning for retirement. I would provide them with information that could help them save more or realize that they are giving what they can’t afford to.

But if you’ve decided from the heart to help your parents or anyone, don’t give grudgingly or with any expectation.

Readers can write to Michelle Singletary at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or singletarym@washpost.com. Personal responses may not be possible, and comments or questions may be used in a future column, with the writer’s name, unless otherwise requested. To read previous Color of Money columns, go to postbusiness.