Cheryl

Hot flashes are NOT a normal side effect for men on thyroid medication. My advice is to schedule an appointment with an endocrinologist, preferably one who went to medical school in the 21st century. While many GPs and oncologists feel comfortable treating thyroid issues, when something like this pops up, more experience is better.
My endocrinologist insisted that my first dosage should be only 25 mcg, then after 3 months and blood tests, 50 mcg - another three months and blood tests, and then 75 mcg. For me the 75 stablized my TSH. Some go on to 100.
I wanted to do the 100 right away but my endocrinologist explained that only by starting off slow and low dosage would we avoid any side effects. According to her, a big drop in my TSH all of a sudden back to what it had been would cause me problems. Plus she was looking to see what forumulation of Levothyroxine would work best. She dislikes Synthroid and has had good experience with Levoxyl, The NIH pages lists all these versions: Eltroxin ,Estre ,Euthyrox, Levo-T, Levotabs, Levothroid ,Levoxyl, Novothyrox, Synthroid, Thyrox , and Unithroid,. The Internet is rife with blogs about how switching from one brand to another made a difference even though they are all technically Levothyroxine. Sometimes it's the binder, or some other factor but most doctors do have a preference based on what works.
These things are tricky which is why it is crucial to get blood tests and take it slow.
What is your husband's TSH level now? My endocrinologist would never even consider changing my dosage without a blood test - which gives an objective criteria.
You have done a great job, but it sounds to me like your husband should be seeing a specialist. It could be nothing more than just needing to start off lower, with a different brand and work the TSH down and the mcg dosage up.
My change from 25 to 75 was spread out over 6 months. My TSH level gradually dropped from 4.3 to 3.04, then to 2.17 and then 1.48 and now 1.36 (before cancer I was 1.6) No hot flashes, no problems except for my IMPATIENCE, (Brian explained it so well in his post)
Oh, and yes, I wore winter clothes during 80- 90 degree days and had zero energy until I got my dosage right. Now I'm back to T-shirts. shorts and working out.
Keep the Faith
Charm