Besides that, don't scrap the game! That's no fun! at least go down fighting!
Playing on until an AI launches, or wins by histograph is neither fun nor educational.
If this would be c3c, I'd fully agree to try to change the tides. But with the crappy Communism and the last SS Parts a lot earlier pre-c3c, it's simply pointless.
He completely lacks economical+research+production base. Not enough Artillery, too many unimproved tiles.
I have no research because i get more income and buy the techs for a cheaper price than if i research or is it better to research myself.
See it that way: If you'd have only a strong Economy (Markets and Banks
everywhere, Stock Exchanges in most cities), better buy.
If you'd have only Libraries and Universities
everywhere, with some Research Labs and a few SCI Wonders, better research.
But face it, you have neither of them.

(In general, you should be able to self-research from Mid-Industrial; trade Techs for Techs then)
How come no more military units, other civs are starting to invade me?
You could easily repell all AI landings with a lot less units, but more Artillery.
May I really strongly advice to download some saves from Regent/Monarch SGs, and have a look at them? True, you'll have to dig a bit for pre-c3c ones, but it is worth it.