Not much option here.
If premium too high, ask siblings share the premium.
Or save up the yearly premium for later use, some semi private hospital like HUKM are price quite affordable.

At age 70 no major insurance company will insure your parent as last entry age is 65.
Seem like GE is your only option to continue medical plan.

Question: Why don't look for other med option at insurance when your parent is younger?
Your story might give some good insight for other reader here.

With regards to annual premium vs cost of medication.

There is no right or wrong in terms of whether you choose to spend or not to spend on the insurance.

Just do some basic mathematics, if your dad doesn't fall sick in the next 10 years, assuming the rate of premium increases at 10% yearly for the next years. You would have paid a total RM245,436 in premium to the insurance company without making a single claim.

Likewise if your dad does get hospitalized in between this period of time, depending on the amount he has to claim, would it justify the amount paying for the insurance policy ?

If the claim is RM245,436 in the next 10 years, then paying for the insurance is worth it, otherwise, if it's below the amount, consider that you've reduced your losses but at a smaller amount.