Pinenut, hello and welcome to TP. I'm sorry you have needed to find your way here.
In your other post, you mentioned your mother has no help and doesn't seem to want any. I assume this means no care package, no carers, no support group, no day care, and so on? That is a separate topic we would address, as you also state she is in her 80s, as is your dad, and we will get to that.
I am bringing this up as I wonder, from your other post, if there is an element of your mother not wanting to discuss the LBD diagnosis at all, not just with your dad. I am basically wondering if there is a bit of avoidance or denial about the illness, on your mother's part, and if that is where some of this reluctance originates.
I may be mistaken and if so, my apologies. I do not mean to be offensive or accuse your mum of anything.
Sometimes this is also a matter of privacy, in that parents may wish to spare their children this information, or don't want to discuss their medical issues.
If it's simply a matter of not wanting to discuss it with your dad, well, there is no one school of thought on this, but I incline towards not discussing.
Many people with dementia have anosognosia as part of the disease. This is a lack of insight. The brain has been damaged in such a way that they cannot comprehend there is anything wrong with them. My mother has this, and so trying to discuss her dementia with her, or her broken knee last year, is pointless. In her reality, nothing is wrong. Her knee isn't broken, she didn't have surgery, she can walk just fine. Challenging, to say the least.
So that is something to consider.
I am sorry that I don't know much about Lewy Body dementia and can't be a huge help there, although we can point you towards resources.
On your other thread, you ask about resources and support in your area. You might contact the Alzheimer's Society as a place to start. You are very wise to get information and help. Please remember that dealing with dementia is a marathon, not a sprint, so be sure to pace yourself.
Very best wishes to you and your family.