Dad applying for a tourist Visa alone. What are his chance?

[Duckcrackling]

Hey
Me and mother applied for a Tourist Visa, together last week and we got accepted.We had the same appointment.
Originally my Dad had applied with us, but he got really sick ( Renal failure)- so we separated his visa application from ours.
When My Dad goes to his interview alone- will this lower his chances? Can he tell them that he we got accepted but he wasn't able to apply with us because of his health condition which improved now.. I know it's always better to apply as a family together but now that's not the case