Re: Vision, Balance, Breathing problems and fatigue. no diagnosis. Could this be mold toxicity?
The suggestion to check for carbon monoxide is a good one. I don't know if toxins might be the problem or not, but our homes, offices and yards are full of them these days. I once had a horrible allergic reaction to the air freshener Oust.
I would suggest getting rid of as many household chemicals as possible and replacing them with natural alternatives. You might also find some helpful suggestions here:
How to Make Your Home a Haven
Clean Your Air and Brighten Your Day with Houseplants
Safe Substitutes in the Bath and Kitchen
One of my favorite sources for natural alternative home products is:
http://www.herbalmusings.com
In the event that you might have some heavy metal contamination, consume plentiful parsley, chlorella and cilantro - those all help bind to heavy metals and help your body eliminate them.
One other thought - besides being exposed to toxins you and your dad likely eat much the same diet. Part of the problem might be due to a nutrient deficiency. I am especially thinking about magnesium, since it is estimated that 80-95% of us are deficient in magnesium and it is really tough to get all you need from diet alone.
All the best,
DQ