He's probably living with his dad because he takes care of the kid for him when it's his custody time and does basic house chores. lbr does Erin strike you as the kind of guy who washes the dishes or does his own laundry? Let alone cleaning toilets. He might sprain his crotch wound.
As for the clothes... I think it's just because Erin is a dude. Most men don't really do clothes shopping that much - styles are more similar, sizes are more standardized, etc. so most men don't spend a ton of time and energy clothes shopping and don't have tons of clothes (some do! ..but most don't). Erin approaches women's clothes the same way many if not most men approach clothes: What's cheapest and will get the job done with the least work/shopping to get it. That's emphatically not how most women approach clothes shopping, not least because they have to shop a lot more just to find clothes that fit and flatter their body type etc.
Like all trans-identified men, especially the straight ones, Erin is just... such a dude. It's part of how you just know this is all fetish shit. They don't even try to avoid falling into male stereotypes. The deadbeat dad, the guy who can't stand shopping and buys the first thing on the rack that's his size, the sleazy pervert who refuses to take no for an answer, the rapist who uses coercion and manipulation to keep his victims from fighting back and/or speaking out... and so on.