Thelma,
I don't know if this will help, but it sounds like my Jim and your father are very similar. Jim would NOT consider taking anti depressants for the emotional lability. Yet, he was suffering so badly from it, to the point that he wouldn't go out of the house due to fear he would cry/laugh uncontrollably. I finally sat down with him, and explained, with the help of the ALS doc, that emotional lability is a symptom of ALS (bulbar ALS) and that is one of the few things about ALS that can actually be treated. That he had a disruption in his brain, (the bulbar area of the brain is responsible for emotional lability) that had NOTHING to do with mental illness. Jim finally relented and began taking very low dose lexapro. (I don't know why he was so scared of it being "depression", it never seemed rational to me, I mean, if you are depressed it is good to treat it if you can, no?) It was almost immediate improvement,and he never again suffered from the feeling of being held captive to his emotional upheavals. He of course still cried, laughed and experienced the entire spectrum of human emotion, but it was all appropriate and proportional to the circumstance. He even looked at me about a week after he started the lexapro, and said with a devilish grin "why did you make me wait so long to start taking this stuff?!".
Maybe if your father is approached in this light, he will see it for what it is, not an emotional disturbance, but a symptom of ALS that can indeed be corrected.
Andrea