It sounds like you prefer the freedom of no kids. Without him around it would be all on you as the parent, seems finances aren't the issue. If that's the case you should get the abortion. If you do think you want to have a child and raise it mostly a single parent then keep it.

I think your reasons are much more complex than "the father's age" and you're doing yourself a bit of injustice to reduce it to that. My biological father was a narcissistic dirtbag, so from that platform of experience I can attest that knowing one's biological parent is no particular guarantee of best life.

No shaming, fair question.

From a societal ethics standpoint I don't see a reason why any decision in this would be reprehensible. Both seem like valid lines of thinking to me.

If your social support is stable enough even without your partner, I think that's doable and might be fine.

Now I'm also considering whether you are able to take care of an aging partner as well as a younger child or teenager which might be another thing worth considering.

I think I personally would lean towards keeping the child but mind you I'm a 30 yo guy with no partner, so I have a very different perspective on this.

Anyway I hope whatever decision you make, you will make it work.

The age of the father puts you at risk. You're more likely to get preeclampsia or have a premature baby.

Do you want to be a single parent or not? How will this affect your life in say ten years? Fifteen ? You will still be supporting this kid in twenty years time, too. I would think of that. Are you one hundred percent you will never become resentful or bitter with this child because you need to sacrifice your lifestyle to take care of them? Your time? Your money? An unplanned pregnancy already is deserving of that question, and with a single parenthood unplanned pregnancy you better be absolutely sure of what you're getting into. It's not the money, it's the dedication.

Are you considering getting into another transactional relationship after this one? A child might make things more complicated too. A lot of men want a lady to keep them company, but not all are happy with a child tagging along.

I'm finding it hard to believe someone would be so ambivalent about completely changing their life like that. You say you would want the best for the child. Can someone have a great life without one of their parents? Sure, but whoever is left taking care of them must be absolutely devoted. You can't backtrack.

It is your life.
Only your decision matters.

But here are some reasons for going through:
Having a kid with no / aging / ailing father is just hard. Do you really need to put yourself and child through that hardship?

Having a kid wih a father that can't do much for it is also hard. Not going to teach Timmy how to ride the bike bc Daddy can't even walk.

I believe there are several birth defects that caused by the age of the genetic material provider. So the health or mental state of the child isn't actually ensured.
Can you provide the child everything it would need? Special needs part undersored.

Reason to keep it:
Human emotions
Human morality

Would the father’s age be a stupid reason to get an abortion?

Yes, if that's the only reason.

Look there's many valid reasons to get an abortion including "I just don't feel like having a child right now". But this baby's potential future relationship with their father, that you don't even know how it will go ... yep that's stupid. People have babies as single parents all the time. In this case the father is still kinda around at least.

It’s a transactional relationship

It's weird to call him a dad if there are no feelings.

The father is definitely a piece of shit for having a child at 70. A fucking geriatric raw dogging his sugar baby (I guess no protection was part of the terms?) is supremely irresponsible.

The only relationship he's gonna have with that kid is as a ghost.