They're actually cousins but the seme is of 'uncle' age.
http://www.mangago.me/read-manga/fushidara_na_hanatsumi_otoko/
Fushidara na Hanatsumi Otoko
thanks but it's not fushidara, it has fewer chapters ><
You can check this tag out
http://www.mangago.me/tag/Uncle x nephew/
thanks ! xD
http://www.mangago.me/read-manga/ore_ni_koi_shite_dousunda/
This one ... But the author dropped it
Yaoi manga, probably about uncle and nephew, (I forgot most of it), seems like the nephew come to the uncles's house to do all the housework. The uncle lost his families and doesn't want another relationship, but he keeps flirting with women.
When the nephew, try to give up. the uncle realize he likes the nephew?
Sorry, but if anyone can help, I really appreciated it. ><