This should be:
Arigato gozaimasu, oniisan...
Doshite samishii nano? Gomen nasai, shigoto isogashikute, amari yukkuri hanashi dekinai kedo, kokoro kara anata no koto aishite imasu....
itsumo aitai desu....
Aishiteru
Tojikomete Eien ni...kimi no soba ni ite... tenshi! chu!
---
It means:
Thank you, elder brother (this is a general term of address, which can used for any older male, not just one's real brother) Why are you lonely? Sorry, I'm busy at work now, so I don't have the time to talk (chat) much, but I love you deeply (sincerely)...
I always want to meet you...
I love you
Lock me in forever...being beside you...angel! smack! (kiss sound) ---
The last line is strange, because it is a male talking to a female. It doesn't match the rest of the text, which is by a female talking to a male...