Hanging around with my brother?

Of course it's okay as he is your brother. There is nothing wrong for guys to be shirtless at home and hanging out in boxers only. Lots of guys do that as it's more comfortable and relaxing at home. I have a friend who is always shirtless at home year round and when his brother is home, he is shirtless, too.

As for workout shirtless together, it is okay too. A bunch of my friends and I workout together in one of guys basement home gym shirtless, too as it's more comfortable. Plus seeing those muscles working motivates us to workout harder, too.

In earlier decades, when brothers often shared a bedroom (larger families and/or smaller houses), ALL this was absolutely standard. Even sometimes going so far as to JO together. (I'm not recommending that, just saying it's been happening for years according to what I read of allegedly true memories from other guys.)

The guy who gave you the negative answer has been infected by the stupid prudery of the 21st century, which doesn't know (e.g.) that locker rooms are to be naked in.

In particular, the mental energy most guys get from working out naked, or at least shirtless, is real and positive. Most CrossFit programs make almost a fetish of their men going shirt-free.

I would personally say (Hell) no, but to each his own! I've heard of much worse trust me. Comparing D**k sizes is a bit much but really its brothers being brothers. From a biological standpoint this is not weird in the least and would be considered a bonding experience and showed that you guys are bold and are comfortable with your bodies!

whatever floates your boats but comparing is a bit awkward.

yes dear you both are gay,