Display form notification on lead based on value from the selected account?

Hi,

I wan't to display a form notification (Warning) based on a value from the target record selected in a lookup field.

Ex. on leads i wan't to show a warning message in the top of the form if the field "Credit Hold / creditonhold" is set to yes for the selected account (Parent Account for lead / parentaccountid).

I found some guidance with javascript - hower this only covers if the field is on the same record. In this example it needs to load the value from the selected account. Maybe the guidance can be modified?

Dynamics 365 form level notification using JavaScript – Dynatecon Solutions