Is Inflamed Appendix Serious Problem With Life Threat?

Dear Sir, My father (61yrs old) recently got severe stumoc ache and has been hospitalized. The doctor (Gastro entrolgist) diagnosed it as Inflamated appendix mass and prescribed antiboitics with liquid diet for 5 days and some tablets for 15 days. Doctor asked my father to visit after this prescription completed, but Iâ??m scared that, my father is very lean and he may not able to sustain long liquid diet for such a long time. I am really worried about whats the next steps.. 1.     Is it a serious issue or life threat? 2.     Why the doctor is not doing surgery immidietly? 3.     I read some papers published on this on internet, looks like sort of conservational treatment; do we need to do surgery after this treatment? 4.     How long he needs to be in liquids? Can we give some solid food? Please advice, heartfelt appreciations for your response.