Family Health Plan [Fhpl] — Cancer Patient denied of hospitalisation charges.

Have taken a family policy from office. which shows cashless claims. 10 days before my father in law was diagnosed with liver cancer and was admitted to the hospital.
we have used my brother-in-law insurance for the treatments. As he admitted my father-in-law as we where out of town. As he got diagnosed he was under treatment.
He was unwell again so we admitted him to the hospital again for the treatment as he had a lump growing on his back. due to the ongoing treatment for cancer.. they cannot put him on more treatment .
while he was at the hospital they investigate and found out that the lump growing is also a cancer as the hospital dint had pet scan and as he was already on medication for liver cancer and as they was improvement we discharged him as he was getting mentally ill and doctor advised as the liver cancer was more serious at the given time .
As he is already on treatment mutiple medication can worsen his health . so we discharged him and claimed for cashless.
fhpl rejected the claim stating its an investigation and the treatment has not been started.
we informed the same to the doctor who is an oncology specialist along with multiple other doctors who where overseeing his case. They told the claim rejection is preposterous as we had 4 to 5 doctors treating him.
So our doctor spoke to the insurance agent and the doctor who rejected the claim.
Who supposedly is bds doctor rejecting claims for an oncology patient telling that if he not treated. we cannot accept the claim in cashless.
Even after the doctor explaining due to complications and the existing treatment. This happened on the one of their network hospital.