First thing to keep in mind is that you worked yourself to death, unless you were very powerful royalty. You worked until you were just too incapacitated to do it, not because you reached 65. This generally meant much shorter waiting periods between the time where an individual can no longer operate independently and the time they passed on.

If you were wealthy, you retired to your piles of money, or if you were noble but from a quickly declining family, you got the education necessary to be a part of the church bureaucracy and got looked over by them when you were old.

If you were a burgher, a lot of clubs and guilds might have a fund set up and contributed to by members to cover burial expenses if someone couldn't afford it and died. You could also go as an elderly person and make a case to the local bishop as to why you needed to beg the church for support, and they'd usually be morally obligated by societal values to hand over enough for a meagre subsistence living. In the times and places where the Church was more corrupt, and more money was disappearing for less moral reasons, those sorts of benefits were often the first support system that was gutted and substituted with messages of helping oneself and being humble.

If you were a peasant, you had a large extended family on some plots of land around you, and there was usually someone to look after someone, lots of childcare and eldercare needs were taken for granted. You would have a wealthy feudal lord who would have obligations in the eyes of society and chivalric code to make sure you weren't just absolutely destitute after a lifetime of work for his family. Some were neglectful anyway, but in a lot of places you could appeal that sort of moral neglect to the sovereign or church bureaucracy and they would use that as an excuse to take over the land, if you thought it would be worth the effort and your standard of living would slightly improve.

I want to make sure I get across that I am a bit cynical about the kindness of church charity or feudal obligations, but those and the sacred duty of the children to take care of the parents made things... less alienated? than we can understand in a lot of ways now that the nuclear family under consumer capitalism has changed our values. Not that any of us now would want to live back then under those objectively horrible conditions, but I want to get across the notion, there was less of a jarring change in life standards than can happen nowadays, where caring for your elderly family is much less of moral judgment thing. You had a terrible life, usually, and the twilight years were not going to be wildly worse than that; nowadays, you can go from a relatively normal life to 20 years in retirement in a spiral of depression and health debt, totally isolated from your family who won't talk to you anymore, and a community with declining neighborly social interactions. For as bad as things were back then, some things are much worse for much longer in certain circumstances for elderly people today, it hasn't just been a total Whiggish progression of elderly management through the ages.

Source note: Some of the stuff I've said here, I got from Steven Pinker or Jared Diamond in various places, and I know a lot of people here disapprove, so I'll just leave a warning