Azure Functions memory / consumption unit usage

The simple answer to your question is "yes".

Use the Azure Monitor Metrics REST API to get FunctionExecutionUnits and FunctionExecutionCount metrics.

This sample call:
az monitor metrics list --resource /subscriptions/<subid>/resourceGroups/pbconsumptionexample/providers/Microsoft.Web/sites/pbconsumptionexample --metric FunctionExecutionUnits,FunctionExecutionCount --aggregation Total --interval PT1M

yields the following sample output shows 153600 MB-milliseconds, or .15 GB-ms:

"name": {
    "additionalProperties": {},
    "localizedValue": "Function Execution Units",
    "value": "FunctionExecutionUnits"
  },
  "resourceGroup": "pbconsumptionexample",
  "timeseries": [
    {
      "additionalProperties": {},
      "data": [
        {
          "additionalProperties": {},
          "average": null,
          "count": null,
          "maximum": null,
          "minimum": null,
          "timeStamp": "2018-04-13T23:40:00+00:00",
          "total": 153600.0
        }
      ],
      "metadatavalues": []
    }
  ],

Here's an explanation of how:

https://github.com/Azure/Azure-Functions/wiki/Consumption-Plan-Cost-Billing-FAQ#how-can-i-access-execution-count-and-gb-seconds-programmatically

For greater context:

https://github.com/Azure/Azure-Functions/wiki/Consumption-Plan-Cost-Billing-FAQ

You can use the Monitor -> Metrics view in the Azure Portal:

For more information on this topic see this functions cost/billing FAQ.