dehlibelly... I'm not terribly familiar with all the other medications, but I'm very familiar with the thyroxine and the lasix, since I take them both, myself...
As you know, Levothyroxine is used to treat hypothyroidism, however, starting an elderly person on 100 mcg is almost unheard of; in fact, starting most people on that high a dosage is quite rare.
Do you know what his actual thyroid hormone levels were when he was started on the Levothyroxine or what they are now?
It takes 4-6 weeks for a dosage change to take effect, so stopping/starting the med on a daily basis won't have an effect. The med that's in his system now, is what's built up over the past 3 months.
If you'd like to post his actual levels, if you have them, in the Thyroid Disorders Community, we can discuss it there. There are certain heart related symptoms that go along with thyroid conditions. Swelling/edema is one of them, as is high blood pressure, but that's not, typically, caused by the levothyroxine.