If the Work Permit (WP) holder’s long-term medical care is for a condition unrelated to work, then as an employer, you can send them home to continue treatment at their own expense.
You can only do this once your employee’s condition has stabilised and they have been deemed fit to travel by a Singapore-based doctor. You’ll have to arrange for and bear the cost of repatriation.
However, you may not send your worker home if they have an existing statutory claim with MOM, such as a work injury compensation claim.