Hello and welcome to Healthcare Magic. Thanks for your query.
There is no medical entity called "anaemia
sleep disorder". Fro the description of your husband's symptoms it is possible that he could be suffering from a "sleep apnoea" disorder.
This is a condition where during sleep, there can be brief periods of cessation of breathing - which in turn could be due to obstruction of the respiratory passages or due to a neurological cause. This causes disturbed sleep and results in the person feeling drowsy the next day.
Please take him to a doctor for a detailed evaluation to find the likely cause for his problem, so that further treatment can be planned accordingly.
Wish you all the best.
Dr. Jonas Sundarakumar