dia daoibh,

an bhfuil sé seo ceart go leor a rá?

"De bharr sin, bhí sé deacair go leor a bheartú céard a dhéanfaidís leis an airgid." should the "a bheartú" be at the end?

I should probably take a break. My brain is fried

GRMA

No, such clauses are at the end.
a bheartú go ... = to plan that ...
a bheartú céard ... to plan what ...

"a" here is not the usual particle as in "rud a bheartú" (do > a, "to") but a proleptic possessive pronoun ("its" planning what ...)