Here, the word लायक means good/compatible. It has no gender. The expression "जिसके लायक" is not a possessive pronoun. It only means "good/compatible for that thing." It should be used as "जिसके लायक" whenever we are talking about a single thing and as "जिनके लायक" when we are referring to multiple things. e.g. 1. Singular form when I am talking about a single girl: I am good (match) for that girl. मैं उस लड़कीके लायक हु. Here the word "के" does not change, as there is no possessive form. Simple it doesn't carry the meaning as "girl's." 2. Plural form when I am talking about multiple things. There are so many girls, for whom I am a good match. मैं जिनके मैं लायक हु, ऐसी बहोत सारी लड़किया हैं. The meaning totally changes when you are using only "जिसके/जिसका/जिसकी" which shows possession of something i.e. thing's. Here the word changes according to the gender of the possession. Some examples may clear these things. 1. He is the same person, whose hand was cut. ये वोही आदमी हैं जिसका हाथ काट गया था. "His hand." In Hindi language, hand is considered as musculine. 2. He is the same person, whose height is less. ये वोही आदमी है जिसकी लंबाई कम हैं. "his height". Height is feminine in Hindi. 3. He is the person, who has multiple virtues. ये वो आदमी है जिसके गुण बहोत सारे हैं. "his virtues." Here "के" is used for plural form of possession. In above examples, "He" possesses all the things like "hand", "height" or "virtues". So the form "जिसके/जिसका/जिसकी" changes as the possession changes.

One answer is give above which roughly tells us the English translation of the sentence. Here, I will try to answer the query why it is "जिसके" and not "जिसका" or "जिसकी". Here the word जिसके refers to the things. The English word for thing is "चीज़", so here "जिसके" means "उस चीज़के". "लायक" means a suitable, compatible, good match, or capable. the meaning changes in different contexts. Here, in such scenario, always के is used. Whenever this word is used to denote "thing" or "चीज़", use "के". Examples: I am a compatible/good match for her. मैं उसके लायक हु. - compatible I am a good teacher, so I deserve this award. मैं एक अच्छा शिक्षक हू. इसीलिए मैं इस पुरस्कार के लायक हू. - deserve He is a good surgeon. So, he is the only one capable of doing this difficult operation. वो एक अच्छा सर्जन है. इसीलिए इस मुश्किल ऑपरेशन के लिए वोही लायक है. - capable

जिसके could perhaps roughly translate, in this sentence, to 'of which' or 'that which'. In this light, the most direct possible translation would be: We must expect from others only 'that which' they are capable of.