Thanks for writing your query.
After reading your post, it seems that your husband is having symptoms which may be due to dehydration as a result of bad diarrhoea
Severe diarrhoea can result in severe dehydration
and electrolyte imbalance
. This may lead to weakness and altered mental state.
You should give him hydrating fluids. He should take healthy diet comprising of fresh fruits and vegetables. This will help him regaining normal electrolyte balance and hydration.
Following investigations will be helpful :-
1. Serum electrolytes(Sodium, Potassium).
3. Complete Blood Count(CBC).
Also get him examined clinically.
I hope this is helpful to you.