What are the principles governing the calculation of future care costs under the BCAA?

In Gao v. Dietrich, 2018 BCCA 372, Justice Savage summarized the applicable principles governing the determination of future care costs at paras. 68‑70:

An award for damages for cost of future care is based on the principle of restitution. In Andrews v. Grand & Toy Alberta Ltd., 1978 CanLII 1 (SCC), [1978] 2 S.C.R. 229 at 241‑242, Dickson J., as he then was, explained the purpose of an award for cost of future care: In theory a claim for the cost of future care is a pecuniary claim for the amount which may reasonably be expected to be expended in putting the injured party in a position where he would have been in had he not sustained the injury. Obviously a plaintiff who has been gravely and permanently impaired can never be put in the position he would have been in if the tort had not been committed. To this extent, “restitutio in integrum” is not possible. Money is a barren substitute for health and personal happiness but to the extent, within reason, that money can be used to sustain or improve the mental or physical health of the injured person it may properly form part of the claim.