good grief, some posters have some kind of humour bypass today, so much angst!
OP, ignore them, the hobo comment is clearly lighthearted and everyone in the RL understand perfectly what you mean.
I change when I go home, mainly because my work clothes cost a bomb and don't need to be ruined too quickly, so I get it.
If someone wants to put on different clothes, fair enough, but why on earth do they wear uncomfortable clothes in the first place is that the only issue?
I think buying your DH some better looking clothes for Christmas is the way forward. Just have a look online, ASOS, Topman, Next and so on, and buy similar from Primark or TKMaxx.
Bit of a shame if you make effort for everybody else but your family. It sounds as weird as people who clean and tidy their home for visitors only. I don't understand the reasoning there either.
Basic respect for yourself and your close ones is the way forward.