Douglas, it's a valuable asset to have had your father take a DNA test. That he lived to such a robust age means that the generational reach of the autosomal DNA test extends further than most.
On his WikiTree profile page, look in the upper-right corner for a drop-down menu labeled "Hylkema-78". In that menu, click "DNA".
Along the top of that display will be a link titled "DNA Tests". Since you are a profile manager for Hielke's profile, you should then see an option to add a DNA test's information to the profile.
The only cautionary note here is that WikiTree currently has almost a thousand errors where a member has added his or her personal DNA test information to the profile of an ancestor who passed away long before DNA testing was available. Maybe the best way to describe the intent here is "one DNA test, one profile." Information about a test goes only on the profile of the person who actually took the test.
I see you also have added your own AncestryDNA test to GEDmatch. If you haven't already done so (but I'll bet you have), adding your father's test data then allows you to create a "pseudo-phased" research kit that, at least partially, will represent a portion of your mother's genome. Basically, the algorithm (with some exceptions) simply looks at what markers are in your DNA that are not in your father's, and then assumes those allele values came from your mother. Though limited in scope, it nevertheless provides you with a good tool to help determine which of your cousin matches are on your father's side of the family as opposed to your mother's side.
