There is a difference between HMOs and health insurance. HMOs generally pay most of the hospital bills while health insurance provides daily hospital allowance as a replacement for the lost income due to being hospitalized.
For HMO, try Philcare. For health insurance, try Philam Life. Philam Life offers daily hospital allowance of P1,000, P2,000, and P3,000 a day. Depending on the plan, they also offer allowances for surgery and critical illnesses such as cancer, hypertension, etc.
As a hypothetical example, let's assume that a person was hospitalized for 20 days because of cancer, was confined in an ICU, and had a surgery. Let's just say these are the details of his plan: P1,000/day hospital allowance, P3,000/day, and P50,000 allowance for the surgery.
After 20 days, he will get P20,000 (P1T a day allowance) + P60,000 (P3T a day ICU allowance) + P30,000 (assuming that his surgery cost P30T). All in all, he gets P110,000 after 20 days in the hospital.
Ideally, HMO and health insurance should go hand in hand. HMOs will cover your hospital expenses which will keep you from looking for money to pay the hospital bills while health insurance will replace your daily income. Going back to the example above, assuming that the person has an existing HMO and almost everything was covered, he gets around P100T from the health insurance company which is enough to cover the necessary expenses not covered by the HMO. If he resorted to debt, at least the debt can be repaid immediately.