Complex sentence: After another long penance of thousand years, Brahma names him a rishi, thus leaving his royal lineage permanently and Brahma suggest him to take Bramharshi grade from his guru Vashista only, as he only has the power to call you as Brahmarshi.
Split into simpler sentences: After another long penance of thousand years, Brahma names him a rishi, thus leaving his royal lineage permanently. And Brahma suggest him to take Bramharshi grade from his guru Vashista only, as he only has the power to call you as Brahmarshi.