Will immigration reject visa if wife is way older than husband?

Hi guys,
So I've a question..its about my best friend who fell in love with a chinese woman but found out shes way older than him..say hes 30 and shes close to 50.but love is blind right! He can easily get any girl in hk but fell for her but the main concern is will the hk immigration dept accept their dependent visa? my friend is not a hk resident so if they get married in hk and she sponsors his dependent visa, will the hk immigration dept accept the visa or reject it? Nowadays immig has gone tough so we dont want them thinking its a sham marriage or anything like that. They both in love ..if older men can marry younger women then why cant younger men marry older women? someone pls reply asap.thanks

@Poison
You didn't say if she was a regular resident of HK, just that she is Chinese. If she is actually a HK person, then Immigration will accept the legal marriage document. They may ask questions, but if both of the people in love can answer in a straightforward and honest way then should not be a problem. Age doesn't have much to do with this type of application, but having a legal marriage does.

hello HKWatcher

Thanks for your kind reply..well yes she is a local chinese resident in hk. and shes around 50 yrs old..bt the guy is abt 30.at first he didnt know her exact age and started to like her bt i guess age doesnt matter to him.So I guess there wont be any problem with his visa as long as the marriage is legal. Thanks