Thanks for posting the question to H.C M. Forum.
Since, how many days ,your father having high blood pressure
and high cholesterol
level, please mention.
In 77 years patient hypertension
and hyper-cholestrolaemia are in itself a serious condition.
High blood pressure ( particularly diastolic i.e.low blood pressure) cause headache, nausea, fullness in stomach ( bloating).
As far as concerned about fever 2-3 vomiting
usually develops fever ( rise in temperature ).
If possible upload various reports.