Marty's Clothes make no sense
Marty wakes up, sees his whole family changed. His whole life is different now, except they still live in the same house for some reason. Now, think about it - EVERYONE wears completely different clothes, except Marty.
Everyone around him wear 'Altered Timeline Clothes' (ATC from now on), only Marty wears 'Original Timeline Clothes' (OTC).
So, why isn't everyone freaking out?
I mean, if your family lives a certain lifestyle, the clothes are going to be a certain type, and you get used to whatever your family members usually wear.
Suddenly one of the family members wear completely different, and probably a LOT cheaper outfit that you have NEVER seen them wear before! Where did Marty get the OTC? Why isn't the family shocked that he suddenly has full set of clothes no one has ever seen before?
Remember that these clothes came from the destroyed timeline, so they basically don't even exist in this timeline, at least in Marty's wardrobe. Marty should have a completely different clothing style, because he has lived a completely different life, with parents that were changed quite a bit in substancial ways. Look at EVERYONE else, and how differently they dress.
The new timeline Marty would be one of family, whose clothes changed, and he would be dressing very differently (in ATC) than the Marty that lived the 'crappier life' with alcoholic mom, wimpy dad and loser bro and sister.
This means, the cheaper clothes that 'our Marty' wears should be shocking the family, at least a little bit. Dave should NOT say anything about Marty sleeping in his clothes again (this habit should also have probably changed anyway), but rather remark how WEIRD and unseen-before his suddenly CHEAP clothes look like! Dave should be AT LEAST AS SHOCKED at Marty's cheap clothes as Marty is shocked at Dave's expensive clothes (though why Dave still even lives there is a mystery)!
Why isn't he? Why isn't anyone?
If your son suddenly comes out of his room wearing much cheaper and weird-looking outfit you have never seen him wear or even own before, with no explanation as to how he got it, since last night he went to sleep in a COMPLETELY different outfit, wouldn't you react and be at least a little bit shocked about it?
It makes NO SENSE.