1year old male dachshund

So unhappy to be rehoming our beautiful boy king, but our 13&1/2yr old Lhasa resents him and we have tried absolutely everything possible for him to bond and accept king unfortunately it just isn’t happening a whole year later and our Lhasa is becoming more aggressive with him and day to day life completely separating them isn’t ideal, fair on either of them or working at all we are beyond exhausted with the situation.
King is a newly turned 1yr old beautiful playful boy up to date with injections flea and worming he’s used to the groomers for pampers and regular nail trims too! He himself is great with other animals as I have a neutered female Lhasa aswell as my male Lhasa and they are great with each other which I will happily show and he happily plays with other dogs when out on walks or to the beach he really loves the beach and he’s used to children due to having our own and being overly pampered cuddled and kissed has made him just love attention he’s very loving.
This has been such a huge decision and not one taken lightly so please don’t contact me if you won’t truly look after him with a whole lot of love too because that’s all he’s ever known from us and I really would appreciate updates of how he’s doing from time to time for peace of mind.
His mother was tan and his father Frankie is a choc and tan who’s quite the father of many eastlancsdachshunds on instagram both mini’s.
If you require anymore information please don’t hesitate to contact me