What wrong with this Cuban Red custard apple tree?

[Tony714]

Hi everyone,

I grafted it on Cherimoya rootstock and its from my brother's house.  Somehow top half is die back but bottom half is pushing new leave.
This is 2x its doing this.   
Anyone has any idea?

[gnappi]

Looks like it's thitsty


Mine did that this last winter but I intervened with 2x per weel soakings with my well water and it finally flushed a month ago, but had some dead limbs to clear out.

My back yard gets lots of water the front no so I pulled a hoae to it and whenever my well pump is on it, the  Pickering and sugar apple get a drink.

[Altrexy]

I’ve heard dormancy can be an issue on cherimoya rootstock. Could be rootstock going semi dormant while the graft keeps trying to grow. My annonas have gone dormant due to thirst

[Tony714]

interesting.  i didn't think cherimoya dormant at this time of the year.
i'll ask if he can increase water.