DEAR ABBY: My elderly uncle and aunt have a son-in-law who — to put it mildly — spins tall tales. “Tom” has been EVERYwhere, done EVERYthing and insists on telling anyone who will listen all about it. He speaks many languages fluently (until someone addresses him in one of them) and has had countless adventures in various countries, although he can’t locate them on a map.

My uncle and aunt have bought two cars for their financially unstable daughter and this phony. Both times, Tom insisted on maintaining them himself (another of his legendary skills). Afterward, both cars required major repairs and eventually had to be scrapped.

After Tom’s stint as a highly decorated Navy SEAL, he morphed into a genius at creating computer software, when he wasn’t touring with a famous bluegrass band — the name of which he can’t remember.

I am concerned that my uncle and aunt are so awed by this man that they might one day allow him to manage their finances (there is no topic Tom is not an expert on) or let him fix the brakes on their vehicle. I think you know where I’m heading.

I have to bite my tongue to keep from saying, “Tom, Yokohama is a city, not a country. And if you’re really best friends with Johnny Depp, why not invite him over so we can all meet him? Oh, and what you’re passing off as Farsi is Pig Latin.”

Is there a way to tactfully intervene before something awful happens without upsetting anyone? — THE QUEEN OF ENGLAND

DEAR ROYAL HIGHNESS: Yes, if you do it privately, and say you are speaking up only because you are worried about their welfare. Then explain why you think Tom’s stories don’t hold water and point out that if he should volunteer any financial advice to them they should first run it past an unbiased non-family member such as their banker, lawyer, CPA or pastor before making any investments.

From your description, Tom appears to be a con man or compulsive liar. But whether your uncle and aunt choose to accept your input is up to them.

DEAR ABBY: I work at home and use my computer. Everyone who lives here is over 35.

My step-grandchildren visit regularly, and I have told the children’s mother that I have no parental restrictions on my computer. She assured me not to worry about it because she has reinforced the rules of responsible Internet usage with them and is confident her children won’t break the rules. As far as I know, they haven’t.

Today, one of my brothers-in-law visited and brought along his young teenage daughter. I let her play on the computer, and he caught her in a chat room with an older teenage boy. Instead of blaming her, he attacked ME for being too permissive with children and computers.

Do you think it is my responsibility to “protect” his teenager on my computer? — JUST A GEEK IN SOUTH CAROLINA

DEAR JUST A GEEK: No, I do not. I suspect that you were attacked because of displaced anger. His daughter deserved the scolding, however, because he could not (for whatever reason) scold her, he directed his anger at you instead.

Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Write Dear Abby at www.DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.