Okay, so meeting your mortal parent, was not on Frank's list on top things to do while questing. But here he was, your mortal parent crying, Jason bringing you back inside after you stormed out. The group of seven were all bandaged up, they had gotten banged up really bad and your mortal parent's house was the closest, Frank got it drilled in his head to respect your parents and elders, so he was baffled by the fact that you began arguing with her. After she had been so nice too?

"Why'd you do that man?"

Frank was upset on your parent's behalf. She'd let them crash at her home after the whole... Rome incident and now you had just gone all guns a blazing. So of course he was going to be upset while everyone else was shivering and sopping wet from the storm around them. He glared you down, upset and annoyed. He was also soaked through the bone, dripping on mosaic tiles and waiting to get a towel instead of just air drying miserably.

You didn't bother to voice any opinions about going to your parent's house. You didn't voice any amount of being upset over being here. So Frank didn't think you could go in, scream at your parent and then rush out all in a fit. It was childish and it detracted from the mission and task at hand.