Your father seems to have CRF chronic renal failure
its natural history is like this that is renal function gradually deteriorates once creatinine
level starts rising it may be fast, You should se a Nephrologist
and find out any reversible cause for rising creatinine. For example dehydration
Infection etc if no then check other parameter and be ready for Haemodialysis may start with formation of AV fistula which helps in hemodylisis.