日记-四月六号

今天我再次去我妈妈的朋友的家。 我妈妈的朋友家叫Lory，和Kevin。Lory 要去工作。Kevin也要上班去工作。今天是Kevin的生日。 在六个小时裡我照看了他们的妈妈。

祝Kevin你生日快乐！ or just Kevin, 生日快乐 The way you wrote does not have the direct effect of saying it to him.

I went to my Mom's friend's house again today. My Mom's friends are named Lory and Kevin. Lory went to work. Kevin also went to work. Today is Kevin's birthday. I watched their mom for six hours.

Happy Birthday Kevin!

日记-四月六号

今天我再次去我妈妈的朋友家。今天我又去了我妈妈朋友的家里。（又is more colloquial)

我妈妈的朋友家叫Lory，Kevin。我妈妈的朋友们叫Lory和Kevin。

Lory 去工作。Kevin也去工作。今天是Kevin的生日。 六个小时我照看他们妈妈。 (watch can be translated into many versions--- 看，注视 照看 etc., among which 照看means look after/take care of, but I don't understand why you need to take care of their mom?or what do you mean by "watch their mom"? emm if their mom is too old to take care of herself, then it makes sense.)

祝Kevin生日快乐！

I went to my Mom's friend's house again today. My Mom's friends are named Lory and Kevin. Lory went to work. Kevin also went to work. Today is Kevin's birthday. I watched their mom for six hours.

Happy Birthday Kevin!

四月六号 日记

今天我又去了我妈妈朋友的家。

我妈妈的朋友们叫Lory和Kevin。（建议：我妈妈的这两个朋友，一个叫Lory，一个叫Kevin。）

Lory 去工作。Kevin也去工作。（建议：他们都去上班了。）

今天是Kevin的生日。

六个小时我照看他们妈妈。（建议：我照看了他们的母亲6个小时。）
祝Kevin生日快乐！

整体建议写成：

四月六号 （晴或多云…）

今天我又去了我妈妈朋友的家。我妈妈的这两个朋友，一个叫Lory，一个叫Kevin，他们都去上班了，我照看了他们的母亲6个小时。

今天是Kevin的生日，希望他生日快乐！

日记-四月六号

今天我再次去我妈妈的朋友家。 我妈妈的朋友叫Lory，Kevin。Lory 去工作了。Kevin也去工作了。今天是Kevin的生日。 我照看了他们的妈妈6个小时。

祝Kevin生日快乐！

I went to my Mom's friend's house again today. My Mom's friends are named Lory and Kevin. Lory went to work. Kevin also went to work. Today is Kevin's birthday. I watched their mom for six hours.

Happy Birthday Kevin!