Applying for medicare soon with my dad - Give me all the advice please!

You might call your state SHIP program, They can guide you in the selection of plans. The Medicare booklet has state specific information about supplement plans available in your area.
Has your Dad been on disability - social security? If so, isn't he already on Medicare?
At any rate, I don't recall any big fuss with the process. I was fortunate in that my employer plan serves as secondary coverage so there wasn't any decision making involved.

Did your Dad take SS at 62? If so, Medicare will be sending him his card automatically. He will get A&B so he will get less in his SS check. Some supplimentals include prescriptions. Are Mom and Dad considered low income? If so, they maybe able to apply to a state prescription plan.

If your main concern is Part D drug plans, get a list of all the meds your dad is on now and check out the plans “Formulary”. You should be able to look at this online. This is a list of meds, name brand and generic, and how they classify them as Tier 1, Tier 2 etc. This will give you the amount they will cover and your copay. Although similar, not all plans cover or classify exactly the same. If he’s on a lot of meds this could be significant. If it’s just generic BP or cholesterol meds might not be that important.
Also when I was managing Moms meds it was helpful to have a plan that I could order refills online and they would mail them to my house, so I rarely had to deal with the doctor for refills, only when the scripts expired, or trips to the drug store. And as been mentioned you need to choose one now, but can switch at the next open enrollment, which can give you more time to investigate.

If Dad not collecting SS then you will need to set him up for Medicare thru ur Social Security office.

Our local Area Agency on Aging has a SHIPP expert that free of charge will look at all his meds, plug into the computer, and advise you of the best Part D program for his situation. They do not work for any particular insurance company so advise is not biased.

Agree with above, my dad got plan G for supplemental and s part D that covered his current meds, it was done by an agent that specializes in Medicare and all that entails.

He’s not on Medicare because he stayed on his private plan since I was still a dependent. He took out social security early because he couldn’t work, but I don’t think it’s considered disability.