Step zero is getting his size as quality footwear comes in width and length. Use a Brannock device or https://www.rei.com/assets/pdf/printable-brannock/nb-printable_brannock/live.pdf to know that he is, say a 7C. Then you can buy 7C boots.

Comfort is a personal metric and one cannot ask this online.

Options:

https://www.thefryecompany.com/collections/men-shoes-chelsea-boots

https://www.allenedmonds.com/mens-shoes/boots/

https://oakstreetbootmakers.com/footwear/everyday-boots

https://thursdayboots.com/collections/boots

https://www.rancourtandcompany.com/collections/boots