I dont neccessarily think there is a problem with it. If there is genuine charity going on, you will be helping the Lord. You can be up front with many and express your own faith. You may inspire some. But I do hope you would be able to attend Mass, if not…that becomes problematic. Lets never demonize protestant bro’s and sis’. But if they are the type who try and “save” Catholics and have agendas to preach against the Church, well…come on…thats not much of a ministry.
The heart of the Lord is mercy. Be gracious and you will learn alot.
God Bless,
Michael
PS, of course you haven’t shared much about their ministry. The denominations can vary just a little bit