Hi @Forever & welcome to the community. Sorry to hear of your husbands stroke.
I’ve never heard of an AAC but if he’s finding that a bit difficult to use would it be worth going back to basics and perhaps having speech cards that he could use instead. Would an ipad help? Of course it depends on his level of ability at the moment with writing / typing etc. I’ve copied in a couple of links to previous posts about aphasia in case there is anything you find useful in them.
There are many posts discussing aphasia. If you type aphasia into the 
search function you will find many more posts.
Others will be along soon to offer their experiences too.
Best wishes
Ann x