Thanks for writing your query.
It will be helpful if you please mention whether your husband is taking any medicine?
The symptoms you have described are usually seen in orthostatic hypotension
. In this the blood pressure falls suddenly on sitting or standing quickly from lying position.
He should be investigated and examined by a physician for the cause of orthostatic hypotension.
He should take precaution while sitting or standing from lying position.
He should not rise immediately from lying position. He should first lie in side position, then sit slowly, wait for few some time and then stand slowly.
I hope this is helpful to you.