Wa alaikum salam
Who said that Allah loves him more than 70 mothers?
He is a servant and a slave of Allah and Allah does whatever He wills! He doesn’t have any right to complain or object.
If he is Muslim, he should know that Allah only chooses the best for him. How would he feel, hypothetically, if he married her and she got HIV and he got it of her? He would be devastated. No one knows the reality of things except Allah and He alone chooses the best for us!