having played on a team with rocket and going over his/our teams demos i can say hes definitely mechanically skilled, a motivated player, and could probably do okay in IM.
but he has a few really bad habits that he needs to fix being 1) he tends to bait a lot which can really mess up no uber team fights because hes always half commited to a fight 2) stemming from the first point he tends to tunnel heal especially during team fights ie he'll heal the furthest person back in the fight instead of the people actually taking the brunt of the fight because he doesnt want to risk his stats 3) he cares waaaaaaaaay too much about stats. he has the thing enabled where if you click on a players name on the scoreboard it shows their stats and not only does he check it about every 10 seconds (if you dont believe me watch his vod) he bm's his team based off the stats he sees if you go down a round or two 4) he tends to countercall because he likes to play the type of tf2 where you take a point get uber again then take another point get uber again instead of trying to roll on other advantages. 5) he does the inexperienced medic thing where he always surfs/runs away from his team when someone is on him and the complains when he dies. also not to mention rocket didnt show up to one match because he was playing fortnite and didnt want to play another match and asked to leave as we were joining the server because he didnt want to have to play with a ringer and it would be a "waste of time".
other than all of that if your team plays a slower style hes definitely a good pick up. considering the caliber of medics in general theres no reason he couldnt play IM he just needs to get those habits albeit mostly habits from pugging so much out of his system and he will be a great player. also rocket is a super nice guy and still young at the end of the day so he has so much room to grow as a player and as a person.