Even if [name_m]Sholto[/name_m] wouldn’t be my personal choice, I have to vote for it because I’ve read your love for [name_f]Sarai[/name_f] and [name_m]Sholto[/name_m] so much that now I can’t picture a different brother for your [name_f]Sarai[/name_f].
My second choice would be [name_u]Tristan[/name_u]. It kinda makes me feel cozy that both [name_f]Sarai[/name_f] and [name_u]Tristan[/name_u] share the same vowels.
I think [name_m]Sholto[/name_m] is the one that best matches up to the distinctiveness and slightly mysterious/eccentric feel of [name_f]Sarai[/name_f]. The repeated initial puts me off slightly, but it’s a different sound so it’s not enough to bother me.
I also really love [name_m]Felix[/name_m], [name_u]Ezra[/name_u], [name_u]August[/name_u], [name_u]Jesse[/name_u], [name_m]Linus[/name_m], [name_m]Otto[/name_m] and [name_m]Bram[/name_m], but I think [name_m]Sholto[/name_m] is probably the closest in terms of the vibe I get from [name_f]Sarai[/name_f], which is cool, unexpected and a little bit dramatic.