Can I apply for Home Caregiving Grant (HCG) if my loved one is unable to provide consent for the application due to e.g. lack of mental capacity or below 21 years old?

Yes.
For care recipient who lacks mental capacity
Care recipent’s donee/deputy# may provide consent on the care recipient’s behalf. If the care recipient does not have such a donee/deputy, the caregiver* may make the application on care recipient’s behalf.
# Donee/deputy must be appointed in accordance with the Mental Capacity Act (Cap 177) and is authorised to make decisions on behalf of the care recipient in relation to the care recipient’s property and affairs.
* For successful applications without a donee/deputy, the caregiver or another family member has 12 months to obtain a court order appointing him/her as a deputy, failing which the payouts will be suspended. For more information on how to apply for a deputyship, please visit SG Courts Website.
Doctor’s certification for mental incapacity is only valid for six months, unless stated permanent.
You will also need to submit the following additional supporting documents:
Doctor’s certification that the care recipient lacks mental capacity OR court order of deputy appointment OR recent medical report stating that the care recipient lacks mental capacity; and
Copy of bank book or statement IF you are nominating an account belonging to a deputy or trustee of the care recipient.
For care recipient below age of 21 years old
The care recipient’s parent or legal guardian^ may make this application on behalf of the care recipient.
^ Legal guardian refers to a person who has been lawfully appointed in accordance with the Guardianship of Infants Act (Cap. 122).
You may wish to find out more here: