Hug those whom you love -
Pour on them every sweet words
until they are sunk
One day you will be facing
reality they won't be back.

I think a tanka is 5,7,5,7,7... And also I had a tiny thing to say.. On the third line it says they.. My assumption you are referring to the words instead of those who are dear. But it can create confusion. Also this piece has a good topic but the tanka sounds a bit force. Specially on the last two lines.

Here are suggestions..

Hug those whom are dear-
Kiss them with every sweet words
Until they feel loved.
one day you will be facing
an open door, and they gone.

Hug those whom you love-
Pour on them the sweetest words
Until they feel loved.
For one day you'll be in shock
as they walk towards the door.

Hug those whom you love-
Pour on them every sweet word
Until they feel loved.
For one day, you'll realize
taht they are not coming back.

Hug those whom you love-
Pour on them affective words
show them they are loved.
Since one day, you'll realize
they have made another life.