Hypothyroism?

After about a year of constantly breaking toenails below the quick, Bo finally took a blood test so we could figure out if something internally was causing his abnormally brittle nails.  We got the test results last night and the vet said that his level of thyroid hormone is low, or hypothyroidism. :(

She said that we have to give him hormone supplements and a fatty diet (BACON!? ...no not really. But a pup can dream, huh?) for 3 weeks and then test the blood again to see if the levels are normal.  If normal levels of thyroid hormone make his nails get better, then he will just have to take hormonal supplements daily. 

After that, if the nails don't get better, they may have to run tests for Symmetrical Lupoid Onychodystrophy (SLO), an autoimmune disease which causes severe claw problems.  This sounds much more serious and quite scary so let's root for Bo's thyroid and nails to get better in the next few weeks!

Any experience with either of these health issues?  Advice/expertise is welcome!