I am sorry to hear this, Kirsten; cant be easy to see your loved one going down like this.
First of all I would put him on a full Iodine protocol; if he is not already? -if so I would increase Iodine considerably. +Boron.
Beware that Depression is a part of hypo thyroidism, the tooth extraction/ mercury may well have triggered this.
" Dr. Brownstein indicates that Iodine is also a chelator of mercury and had tested quite carefully the amounts removed.[xxiii] Mercury not only poisons the nervous system and digestive tract, it can also poison the thyroid gland. There are 4 iodine binding sites or receptors on the thyroid gland. These receptors bind with the iodine we get from our diet. The iodine enters the thyroid and activates it. If the thyroid is not absorbing enough iodine it will not be fully activated and the body's temperature will be abnormally low. Mercury from dental fillings can migrate to the thyroid gland and sit on one or more of the thyroid's 4 iodine receptors blocking the iodine from reaching the receptors and activating the thyroid. When this happens iodine is not absorbed in normal amounts by the thyroid gland. The result is low body temperature or hypothyroidism"
" Dr. Abraham noted that in some patients the excretion of lead, cadmium and mercury increased several fold after only one day of iodine supplementation and that increased aluminum excretion was noted about a month after beginning supplementation. Orthoiodosupplementation induces a detoxification reaction in some patients with high bromide levels. The symptoms include increased Body Odor and cloudy urine. The Body Odor lasts one to two weeks, but the cloudy urine may last several months before clearing up. Side effects can be minimized by increasing fluid intake. Increased fluid facilitates the excretion of excess iodine and the bromides, fluorides and heavy metals that the iodine displaces. Dr. Abraham also reported that the administration of magnesium in daily amounts up to 1200 mg eliminated the Body Odor but not the cloudy urine." http://www.alkalizeforhealth.net/Liodine2.htm