The shirts are nice but the cost implication is the other. For someone in Canada or the US, he won't have any problem but for someone whose currency is say 200:1, a sweatshirt of 50CAD would amount to 10,000 which is not cheap without taking into consideration the cost of shipping. Your post is not explanatory enough as I expect that there should be a follow-up on how to go about it. You provided a vague information.
does this online store only sell clothes for bitcoin, why is there no purchase feature through bitcoin or ethereum.
What would likely happen will be that he will collect bitcoin and ship to you rather than paying on the website because there is no option to pay with bitcoin on the website.