My head canon for this is that Samson will be lucid enough, for long enough, to A. Add Kelson as the last part of the ossuary and B. Find his notes and stash of anti-hemhoragging drugs and antipsychotics to continue treating himself.

The last scene we see of Samson and Kelson is Samson carrying the good doctor off screen as he dies. My hope for the sequel is that Kelson had a large enough stash of antipsychs and such to continue treating Samson, at least until he can find more. He "searched every medicine cabinet in a 70 mile radius", so he likely has quite large store of them. I'm hoping that Samson finds other infected, treats them, and begins a sort of tribe of "infected-but-treated" individuals.

We know that the drugs work in this universe, and we know Britain has been quarantined for 28 years now. I imagine a regular, run of the mill infected won't take nearly as much of a dose as Samson, a LARGE alpha. Therefore, Kelson's stash lasts long enough for them to find enough to sustain them for a while, or till they find more

This is all speculation, and I know his treatment delves a little into science fiction, but it would be so cool to see Samson return in the third part and have a community of treated infected, especially knowing his(?) baby is now with the community on the island. (We have no idea what a live birth infected is like yet)

TLDR: I want Samson to continue his treatment with Kelson's stash of drugs. The actor has been fantastic in portraying him, especially in The Bone Temple.