I think your plants will make it - but you will need to act fast
that shriveling appearance of the main stem (caudex) means the plant(s) are not getting water ...spraying twice a day is not nearly enough .....
for now - saturate the sand - be certain there is ample drainage to allow excess water to flow out of pot
try to repot the plants - as soon as possible - in a half and half mixture of regular potting mix and sand ....
keep that mixture damp but not dripping wet ....
as the plants get a little taller, added few more leaves and the caudex has filled out more - repot each plant into its own pot
a glazed pot is fine - an unglazed pot is better ....what-ever you decide - make sure there are at least one hole at the bottom of pot
adenium have absolutely no respect for expensive pots - as roots expand - pots break
In the meantime - gather together
1 Part: Coconut Coir -
1 Part: Redwood Bark (or) Orchid / Phalaenopsis Mix - Break-up, cut or crush larger stems & bark
1 Part: Poultry Grit (or) Pea Gravel
1 Part: Perlite - coarse -
1 Part: Sand - coarse / large grain sand = Leveling, Horticultural, Builder's Sand > screen out fine sand & dust
1 Part: Lump charcoal - Break-up, Crush to 1/4" to ½" sized pieces > screen out dust
1 Part: Lava-rock – (volcanic cinders or pumice)
mix together - the resulting mix is a chunky - gritty mix that is fast draining
I believe the yellowing leaves is from lack of water
wait a couple of weeks on the fertilizer - start off with a liquid fertilizer made for cactus / succulents in the NPK range of 2-7-7 or 5-10-5
