As you have seen by now, in sign language personal pronouns are carried out as indices pointing at the referents present or towards the points in space associated to the absent referents, such as "you", "me", "him", "we"…
And as you will also be aware, such pronouns may be omitted or not when directional verbs or the auxiliary agreement sign are used.
"Please, can you let him/her know?"
"I'm missing my children very much."