Taeyang sends handwritten letters to T.O.P and Min Hyo Rin?

Why did Taeyang write a handwritten letter to T.O.P?

On the December 28 airing of ‘Radio Star,’ T.O.P revealed that Taeyang sent him a letter. Taeyang explained, “T.O.P was going away to Germany for 2 months and he was having a lot of difficulties because he also had to prepare for a BIGBANG concert. I wanted to encourage him, so I wrote him a letter.” 

In the letter that was revealed, Taeyang writes to T.O.P, “To Seunghyun hyung, I will be praying that you go to Germany to film and get back safely. I will miss you a lot for 2 months while you’re gone. These days, you look more tired and lonely, so I am always worried about you. Cheer up, hyung! Every night, I pray for your soul and for you to one day realize God’s love that the Bible talks about. Have a good trip. Hyung, I love you!” 
T.O.P revealed that he was really touched by the letter, especially by the part that read, ‘I love you,’ since guys do not really say that to one another. 
Taeyang also shared that he frequently writes handwritten notes to his girlfriend, Min Hyo Rin. He explained,”Sometimes I mail it, sometimes I give it myself with flowers.” 

Source: allkpop