1973 starcraft capri 120 GM 153 I/L4

hello my boat was stuck in reverse, had someone work on it and now I have gear lube oil leaking from air intake holes. I think O_ringwas not replaced??? adjusted the shift cables and had muffs on it in driveway and some water was coming in back of motor now he says I have a blown freezeplug??? Was hot out and never did this before???? we took boat out and kept it on trailer (just in case) started right up no water leaked in back but still stuck in reverse!!!! really tired of boat issues, never had all these other problems before!! any help is greatly appreciated!!! thanks in advance!!!

get him back to fix his work!!!!!!!!!! remove cable from inside the boat and try to manually shift it. If you cant move the cable ,drop the lower unit and try to move the cable,still cant move it,remove the upper unit and try again.

rather no!!!t gonna try to fix myself, that's what I should've done 1st time, the gear lube leak is coming from in between the upper and lower unit. my guess its coming from upper then??? we also had cables adjusted in driveway had all gears but only had reverse in water, wonder why that is?? was told you cant adjust in the water is this true??? thank you for your fast reply!! its really appreciated