Bromine detox is helped by copious amounts of water together with chloride. In general we recommend sodium chloride, but for people who can't handle additional amounts of salt, potassium chloride is a wonderful alternative. To my knowledge, there's nothing about it that will enable you to lose weight. If you're low in potassium it will help. But if your adrenals are stressed due to low-functioning thyroid, extra potassium may not feel very good. Just be aware of the possibility.
I'm more concerned about your low thyroid. You said you've had to watch your weight since 2006. You're keeping the hypothyroid in check with supplements. I think it's possible that these problems you describe indictate that your thyroid function is not optimal and is in fact a huge stumbling block for you. Go to Stop the Thyroid Madness and see if you recognize yourself there. I'm concerned that you'll flail around for too much more time, and you deserve to be enjoying your righteous age of 58 :)