from IRS PUB 502 medical expenses
What Expenses Can You Include This Year?
You can include only the medical and dental expenses
you paid this year, but generally not payments for medical
or dental care you will receive in a future year
from PUB 969 HSA
Qualified medical expenses. Qualified medical expenses
are those expenses that would generally qualify for
the medical and dental expenses deduction. These are
explained in Pub. 502, Medical and Dental Expenses.
thus I conclude the prepaid portion can't be reimburse by the HSA. You might want to ask the practioner if they will provide you with a statement of what portion of the prepayment was utilized.
another option - no authoritative support - is to prorate over the period of the proposed treatemnt so if it was 25 months that would be 4% for each month of treatment.
