how can "onun evi" mean "His house" and at the same time mean "The house of that" ?

the house of his - onun evi/onun olan ev

the house of that - şunun evi/şunun olan ev

in the turkish lessons here in grammar it says:

onun evi = his house

onun evi = the house of that

eh...?

there is no gender in turkish

maybe they mean the house of it

o kedinin evi

I know. it isnt what i asked about

ok....i dont know. but its written like that in turkish lessons grammar

o = he/she/it/that

maybe they mean the house from him/her/it

onun evi satıcaklarmış

they are going to sell the house of him

in the turkish lessons here in grammar it says:

onun evi = his house

onun evi = the house of that

btw, not "that"

that = şu