sponsor

One of my maternal uncles passed away and he had six children. Can I sponsor one of his children or does sponsorship of orphans not apply to relatives? If it is permissible to sponsor him, will this sponsorship be regarded as valid, as I am in one country and they are in another country? Will it be sufficient for me to send a sum of money each month as well as taking gifts to them when I visit once a year during my annual leave? Can the money I send be given in two installments each year?