There are probably a couple things at work here. He’s always been controlling, but now he’s missing that brain “filter” that stops him from saying or doing certain things. Also, he could have depression. Depression and dementia often go hand-in-hand, and depression makes a person a lot more frustrated and irritable. I would talk to your physician about doing a GDS (Geriatric Depression Scale) score and maybe seeing if the physician would recommend any anti-depression medication to help even out your husband’s moods.
What irritates him the most? It’s always important to track behavior and find out what happens right before it, which will tell you a lot about the potential cause. If it just seems like it’s all of the time, that’s important to know, too.
Hope this helps! Let me know.