Separation pay and Retirement benefits for Project-based employee who died

Good evening. Let me start by saying that my father have worked for Taisei Philippine for 9 years, from 2005 until before his death last month Sept. 16. There was a period when he was terminated by the company because he wasn't signing the Project based contract offered to him in different length of time, a 3 month contract, 1-month contract, etc but all reiterating that he was not a regular employee. He had that issue filed with assistance from DOLE and he was re-hired, but still was a project employment.
My first question is, from 2005-2013 wouldn't that have been a basis for regularization? And would that dismissal from work affect his tenure of 9 straight years thus a basis for him not getting his retirement pay? Is he also entitled to a separation pay? The company insists that he doesn't qualify for retirement pay because of the illegal termination that happened last 2009 that would make him only 4 years in the company. Please help us. Thank you.

with that length of service, he should have been a regular employee because his work is necessary and desirable to the company. He can file a labor case before the nlrc.even for 4 years, he should have been regularized

he was demanding the company to make him a regular employee, to be given benefits of a regular employee but they still specify in the monthly contract that he is not considered a regular employee. their contract is really only for the benefit of the employer. the company issued us a check with an amount less than his monthly salary, almost the same as the salary of a probationary employee and said my father doesnt qualify for a separation pay or retirement pay because he wasnt able to file it. what a great company.