Cactus / macdowellii

This is a degrafted Ariocarpus kotschoubeyanus v macdowellii f albiflorus.
It seems very weak and looks like just surviving.
I bought seeds and sowed on 30/09/2004.
Several seedlings were grafted onto Hylocereus stocks and degrafted later.
Only one has survived.
I have to think about how I can increase numbers because I just have one plant.