Do you find this weird?

My friend who is only 22 and he is in very good shape 5'10 nd extremely built(body builder), but he recently started dating a 30 year old obese woman(has to be over 300lbs)... He brung her over for a BBQ and i just found it very odd, they started making out in the chair and i thought she was going to crush him, everyone was staring at them... He is also Irish Catholic descent and he recently moved down here from NYC to Georgia with his family and met up with this girl.... Is there something in the Irish or Celtic culture where they date Obese woman?? I am not gay, but he is not a bad looking guy either... I just find it extremely strange.