Do we need life insurance before the motgage can go through or is the adviser tyrying to sell us insurance that we don't yet need?
No, but you do need Home Owners insurance. Are you sure you've got the types of insurance straight?
Home owners insurance covers your property and personal belongings in case of a fire, burglary/theft, hail storm, etc.
Life insurance covers the policyholders life in the event of a death.
However, there is mortgage protection insurance that will pay off the mortgage if you die before having paid off the outstanding mortgage.
In addition, some people buy mortgage term life insurance to provide money to pay off the mortgage, and possibly leave money to their partner/spouse, if they pass away before paying off the mortgage.