A friend's husband had surgery last year, and there were some ill results. The brother is mentally alert and wants to attend Jumu'ah prayer. He has a catheter and bag to relieve himself (urinate). As long as he makes Wudu with the intention of going to prayer, is it all right for him to pray? There may be some leakage, as he has no control.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The prayer of anybody who carries impurities be that in a plastic bag or on his clothes is invalid even if the bag is completely sealed.
So, if the person can remove this bag, empty it and clean it before praying he must do so for his prayer to be valid. But if he cannot do so, or if this constitutes much hardship for him then he can pray with it as Allah Says (interpretation of meaning): {Allâh burdens not a person beyond his scope. …} [2: 286].
Know, however, that the coming out of this urine nullifies the Wudu. So, if it is continuous, the person has to make a new Wudu for every prayer just before performing it and anything that comes out ultimately does not alter the validity of the prayer. There is no difference in this rule between Friday prayer and other prayers. However it should be mentioned in this respect that if the catheter he is carrying smells bad then it could harm the other praying people and if it leaks it could spread impurities. If these things could not be avoided then this person should pray Zuhr at home instead of Jumu'ah, at the mosque.
Allah knows best.