Could this be dementia?

Lots of things can cause this as lots of people have said.

The best way forward is to get him to the gp for a memory test. If he doesnt accept that he needs this, his wife can call the gp and express her concerns prior to a routine appointment.

Forgetfulness isn't always the beginning of dementia. The first sign is often word-finding difficulty - starting a sentence and then not being able to find the words you need . Forgetfulness is often just "the brain cells getting old and worn out" so to speak. But the best thing to do is to see the GP and go from there.

I think as we get older we tend to worry about dementia and become very aware if our partners or ourselves seem to forget things. Men are notorious for not really listening to their wives, my father used to be like that, telling people that he was always the last one to know and now my DH seems to do the same! But as others have said if she's worried a check up with the GP would put her mind at rest.

No he's very capable around the home, she's got a real gem as he helps cook, clean, does DIY etc. She's worried tho as says he doesn't remember things she tells him and him completely denying he even saw or mentioned the shed has really thrown her. Think there has been quite a few instances of forgetting things being said and it's getting more frequent. Thanks for your replies xx

That just sounds like forgetfulness. Does he have problems with everyday tasks?

Sister must be so worried. She will notice little things that others do not; and they add up bit by bit.

I do hope that it is not dementia. She is going to need your support.

I'm sorry you have this worry to deal with. I don't think anyone here can answer your question one way or the other, though. Your BIL needs to see a doctor and get an assessment done. If it's simply forgetfulness, that would be cheering. If he does have something more serious going on, then it's best to have an early diagnosis in order to gain the best treatment as soon as possible.

Wives/husband’s tend to be the first to notice any changes. My SIL was adamant that my brother was showing signs of dementia years before he was diagnosed and long before the rest of us thought that anything was wrong. Worth getting checked out as the sooner diagnosed the better.

Sometimes people are just not listening when you’re telling them something or they may be concentrating on something else and just saying ‘yes’ automatically
I think you d need more than that incident to worry about dementia to be honest