First thing is that the pipe is lead and those are joints are wiped solder joints. They do not allow you to connect into the toilet bend like that any more. You will have to take out T and replace with new Nohub tee with 2 side inlets are a nohub tee and double y below. You cant bend the lead to fit either one of the fittings because you will kink it, and our code does not allow you to use a nohub band on lead, you have to have a ferrel on the end, and if you try to do the job and cut out tee your stack might come down, it has to be supported and also you need a permit for that job taken out by Lic. Plumber, check your local code.
Art retired plbg