ma'm, thanks for coming to HCM. as is implied from your question that your husband has been diagnosed as hyperthyroid and started on antithyroid medication along with supplement of vitamin B12
and vitamin D. ergocalciferol
is vitamin D which is given as a supplement therapy to most of the pt with chronic diseases specially if they are vegetarian by diet. the dose is as you have mentioned , it is 60 000 IU once a week. you must give him calcium as well along with vitamin D. for dose and availability of brands you must see your doctor. regards!