Hi Piotr,
One of my friend use remitano website to buy crytpo in Malaysia and he is quite happy with the experience. This is not an exchange and sellers and buyers are registered in the website. It's like a platform having buyer and seller together and we just neer to pick a high rated seller and and then deal. I heard that remitano works as mediator and ensure that transaction is successfully closed.
Your friend can try it and he can make the payment using bank account. It's available in Singapore as well but I didn't use because I use Indian exchange to buy.
Hope this information helps. If need more information about remitano or any query then I can help.
Thank you so much.