Neglecting Jumah prayer is like neglecting any prayer. If he does not go to the masjid even though he is able to then he is sinful. This relative of your is deviant and ignorant.
http://islamqa.info/en/7699

I have a male relative who claims to be very knowledgable in islam to the extend that he calls himself an imam. However, he is of the opinion that you can miss the jummah prayer on Fridays as long as you have not missed it 3 times in a row. So sometimes he prays at home for two fridays and he goes to the masjid on the third Friday. What is the punishment for missing 1 or 2 jummah prayers on purpose?

Prayer | May 9, 2015 12:20 pm
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 I have injury in my leg and I found a prayer hall at clock tower from where we could see the Kabah and if you look down it looks like the area is part of the Al Haraam.  people are praying in congregation following the Imam of al Haraam and they hear the imam via sound system. Is it permissible to pray in this prayer ?
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When I went for Tajweed class, during the Asr time, sisters made their own jama’ah after the adhan in the cellphone but I did not join them. Then the imam made adhan and I waited for half an hour for the iqama. But there is no one in the brother’s section so I started to pray alone. when I finished praying, the imam called for the iqama so then again I joined the imam in salah. Is my salah valid?