VINCE, I don't know the dates in which Zane returned those photos, but I believe that he has not been well lately, so if those photos wee returned recently, there may be a valid reason.
I have not spoken with nor seen Frank nor Christine in the past 12 years and his medical condition as stated above is most likely only a RUMOR, so sdon't place any validity in what I said above.
I only recall that both Frank and Christine were extremely well liked and polite individuals and I cannot picture him acting in the manner in which you stated without some valid reason.
Frank is at an age where forgetting some things in the past is relatively common.
I noticed that about Larry Scott also a year or two before he passed away.
I cannot think of any other reason why he would act that way.