This looks like a vocabulary mistake by the original author or an error introduced by an editor. The word "leach" fits better. Rain leaches minerals from soil. Time leaches details from memories. leach | litʃ | verb (with reference to a soluble chemical or mineral) drain away from soil, ash, or similar material by the action of percolating liquid, especially rainwater: [with object] : the nutrient is quickly leached away | [no object] : pesticides that leach into rivers. • [with object] subject (soil, ash, etc.) to a leaching process.

Hi, Great question. It is linked to a "leech" which is a worm that can attach itself and suck blood from you. In this sentence, the word is being used to infer something like time drains your memories. Without seeing your quoted sentence, I would have struggled to come up with a valid use of "leech at". I might sometimes say someone or something leeches at something to mean it drains it (perhaps even slowly drains). His petty comments every day about our progress leeches (away)(at) our morale. Seeing Chris's answer, I was wrong. This helps: https://www.thoughtco.com/leach-and-leech-1689431

A leech is a type of worm that is known to bite onto animals and suck out their blood. So the verb form "leach" comes from that, describing one thing draining something from another. In a literal sense, a leech can leach blood from an animal. Or you can also say something like, "Too much exercise leaches all my energy." In the example you gave, it means that the years (meaning time) have caused him to forget things. Time has drained him of his memories. Another use of the word leech can be to describe someone who "freeloads" or exploits someone else for their own gain, often without contributing themselves. In that example you could say, "The man refused to get a job, so he continued to leach off his parents." This is not the meaning in your example, but it is handy to know. :) I hope that helps, and feel free to message me if you're still confused.

A leech is a blood sucking animal that attaches to your body and slowly drains you. So the use of the word is to slowly take away. Time slowly takes away his memories. If someone is called a Lee h, it's a bad thing. It means they are slowly taking something from someone else for their own benefit. My neighbor is such a leech because he's always picking my flowers when I'm not home. Please stop leeching off of me! It's actually not a common word that people use, but it's very descriptive!