Hi and welcome to the forum though sorry for your need to be here.  I am not sure how best you can get round the Fathers' Day dilema.  When my hubby was terminally diagnosed  he had days when he just needed to be left alone to deal with his own emotions (hated being ill and showing how he felt to me and our adult kids).  It was particularly difficult in the final months birthday, Father's Day and Christmas all came with difficult emotions both for him and us all as a family.  If he lives close by it could be worth just 'passing by' and not stopping too long thus not tiring him too much but giving you and your husband at least the chance to see him.  My husband thought he was protecting our children  and me by 'shutting down'himself and  it took gentle persuasion (and some craftiness) to  get some of those visits to take place.

I hope others will be along to share their thoughts too and wish you all the best as your travel this difficult road as a family. Jules54