My Dad has had dementia for over 10 years. He doesn't speak but recently he has become aggressive. Any tips to help?

Get him on meds to make him comfortable. If he is in pain he can't tell you what is irritating him. Talk to the MD about what meds he might need.

I found this article on the Aging Care website, hope it will have suggestions that will work for you. https://www.agingcare.com/articles/causes-of-alzheimers-anger-143103.htm

For other article regarding Alzheimer's/Dementia, go to the blue bar near the top of this pay and click on SENIOR LIVING, now click on ALZHEIMER'S CARE... now scroll down through the articles. The more you know about this terrible disease the more you will understand what is happening.