I think It would be pretty similar to how gojo raised him,depending on the route we take,if it's the cult one,suguru would be more twisted and obsessive,Highly manipulative,but either ways he would be pretty clear and honest with whatever feelings he possessed for the boy, creating an environment where megumi could let himself lean upon suguru without any hesitation,and I think megumi would admire that level of honesty and "unshakeable" Moral principles from suguru's ideology,depending on the role of his sister, megumi may or may not completely support suguru's cause but he may be inclined to stick by the man's side for all suguru has done for him.

And if it's suguru not turning and becoming a sensei route, I imagine satofushisugu to be this one family, where they are overly possessive and obsessive over the kid they raised,and also I believe suguru wouldn't push/pressure megumi to be the "strongest" To be able to stay by his side, to challenge him to his potential and would instead be content in just taking care of him as his protector.

I hope it's to your liking pretty flower!!🌻🌸 let me know if you would like more! I greatly missed sugufushi and was so thankful for this ask!!🙇‍♀️