I can't see how he would object to boxers, i had a girlfriend who wore them a lot, because they were more comfortable, and didn't show a ''panty line'' when she wore them under tight jeans, i don't think you have anything to fret about, wear them, wash them at home, it won't be a problem, i'm sure he would be fretting more, if you wore thongs all the time.
if he is a good dad he would not judge you.
As long as you wore something OVER the boxers....I wouldn't have a problem with it. They ARE rather comfy! =)
I'm not a dad or a guy for that matter, but if my daughter chose to wear boxer briefs, that would be fine with me. Personally, I would never wear boxer briefs as I prefer thongs and g-strings, but I say each to their own, and let live as be.
I would think it was funny. I don't see the need to criticize you for it. And yet if my son wore women's underwear I would be pissed.
They would be more comfy, and similar to bike shorts, you can layer under shorts, or shorter skirts. However, he might get upset because you are taking his, instead of wearing your own! So, you liable to hear anything if he doesn't have his to wear, and he don't like yours either. So, leave his alone, until you can buy your own, and remember that if he comes looking for a pair.