I had never considered that the father of a girl baby/toddler would ever have to ask that question. It seems clear that a father's role and involvement during this age is as important as her mom's....and that includes her personal care. Putting an adult spin/concern on the natural day-to-day care like bathing/diapers shouldn't be an issue. Please reassure your husband that he's doing all the right things by being a hands-on father.
If he still worries, I'd ask him about single-dads, gay fathers, and grandparents raising their grandchildren. There are a lot of men raising baby girls ;)
The only caveat I would add, is if caring for his daughter in these ways, makes your husband FEEL awkward (despite reassurances above), if he came from an abusive childhood (and it may be raising up the past for him), or if your daughter ever expresses that she feels uncomfortable with him during these times...than by all means, do what feels right for everyone involved.
Little babies/kids are natural, innocent and un-jaded. They don't sense the shame and embarassment over nudity, etc that we as adults do. Most times, kids become that way only when an adult's action/words imply that they have something to be uncomfortable about.
Hope this helps!
Best,
C.