'd是would的缩写 You would be so proud of him
be proud of=take pride in以...为傲
would是will的过去式
would一般用于过去将来时：主语+would（should would）（not）+动词原形+其它
would be表示对将来的假想,并且是虚拟语气
would be = will be的过去式,用以表示未来,还有个情况就是表示可能