My Fiance Has Symptoms That Match Some That Are Endocrine

my fiance has symptoms that match some that are endocrine issues. thirsty, to hot/cold, & tired/sluggish. He has some other health issues as well (sleep apnea, hypertension, & high cholesterol) so i wonder if symptoms overlap, & should we ask his regular physician to test & if so is there a particular test we need to request?