This past week my mom who is 80 has been facing an interesting happening.

When my dad had his heart attack 16 years ago at age 62 he stopped having sex with my mom as he was afraid it would cause a heart attack.In fact he gave up a lot and became very sedate amid our disagreements that he do that.

Starting the beginning of this week my dad's interest in my mom sexually has returned and my mom has no problem with that. However, he now is convinced that she is also having sex with one of his many male hallucinations and that makes him angry.

My dads way of showing anger has always been to "clam up" and so now he barely mumbles to my mom all day and maybe eases up a bit by later in the afternoon?

Is that part of the LBD?

Having delusions (especially about infidelity for a married person) can be part of LBD.