I want to knit a sweater for my dad, and I found a pattern for this raglan style sweater he really liked, the problem is it only has instructions for sizes 36-42 inches and I need 48 inch (these are for chest measurements). I was wondering if increasing the size would be as simple as just increasing the number of stitches or if it would be more complicated? Since this is a raglan sweater I’m worried that I may have to modify the amount of stitches I decrease for raglan shaping and how frequently I decrease, etc. I’m not a very experienced knitter and if it gets to complicated it may be better to just search for another pattern that’s similar 
link to sweater pattern: https://www.etsy.com/ca/listing/526202499/mens-fishermans-rib-sweater-knitting?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=men%20sweater%20patterns&ref=sr_gallery_31

thank you !